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python element order in dictionary

pas you are using django you could use codesorteddictcode a hrefhttpdocsdjangoprojectcomendevrefutilsdjangoutilsdatastructuressorteddict relnofollowdocsap

setting the fmt option in numpysavetxt

pyou can use the codefmtcode parameter in many ways here are some examples to give you some insightp precodeimport numpy as np a nparray11121314 21222324 codepre p1 codenpsavetxttmptxta fmt13fcodep precode11000 12000 13000 14000 21000 22000 23000 24000 codepre p2 codenpsavetxttmptxta fmt04dcodep precode0011 0012 0013 0014 0021 0022 0023 0024 codepre pyou can also use to write expressions like note that the number of entries in the expression is the same as the number of columns in the arrayp p3 codenpsavetxttmptxta fmt11f 11f 11f 11fcodep precode110 120 130 140 210 220 230 240 codepre

python script doesnt terminates after a long time when its finished

pdont call codereadlinescode that loads the entire file into memory beforehand you can just iterate over codefcode directly and itll work finep precodewith codecsopenhugefile r encodingutf8 as f for line in f codepre

prepending zeros to a list

pthis might work i have not tested it myself but i think it should be finep precodedef addzerobinarylist if lenbinarylist lt 8 zeros 0 8 lenbinarylist return zeros binarylist else return binarylist codepre

convert curl i user to python requests

pusep precoderequestsgeturl authusername password codepre psee the section on a hrefhttpdocspythonrequestsorgenlatestuserauthenticationbasicauthenticationbasic authenticationa in the coderequestscode documentationp

python unhash value

pit cant be donep pa hash is not a compressed version of the original value it is a number or something similar emderivedem from the original value the nature of hash implementations is that it is possible but statistically unlikely if the hash algorithm is a good one that two different objects produce the same hash valuep pthis is known as the a hrefhttpenwikipediaorgwikipigeonholeprinciplepigeonhole principlea which basically states that if you have n different items and want to place them into m different categories where the n number is larger than m ie more items than categories youre going to end up with some categories containing multiple items since a hash value is typically much smaller in size than the data it hashes it follows the same principlesp pas such it is impossible to go back once you have the hash value you need a different way of transporting data than thisp pfor instance an example but not a very good one hash algorithm would be to calculate the number modulus 3 ie the remainder after dividing by 3 then you would have the following hash values from numbersp precode1 gt 1 lt same hash number but different original values 2 gt 2 3 gt 0 4 gt 1 lt codepre pare you trying to use the hash function in this way in order top ul lisave space you have observed that the hash value is much smaller in size than the original datali lisecure transportation you have observed that the hash value is difficult to reverseli litransport data you have observed that the hash numberstring is easier to transport than a complex object hierarchyli ul p p pknowing why you want to do this might give you a better answer than just emit cant be doneemp pfor instance for the above 3 different observations heres a way to do each of them properlyp ul licompressiondecompression for instance using gzip or zlib the two typically available in most programming languagesruntimesli liencryptiondecryption for instance using rsa aes or a similar secure encryption algorithmli liserializationdeserialization which is code built to take a complex object hierarchy and produce either a binary or textual representation that later on can be deserialized back into new objectsli ul

including nonpython files with setuppy

pstrongto accomplish what youre describing will take two stepsstrongp ul lithe file needs to be added to the source tarballli lisetuppy needs to be modified to install the data file to the source pathli ul pstrongstep 1 to add the file to the source tarball include it in the manifeststrongp pcreate a a hrefhttpdocspythonorgdistutilssourcedisthtmlthemanifestintemplatemanifesta template in the folder that contains setuppyp pthe manifest is basically a text file with a list of all the files that will be included in the source tarballp pheres what the manifest for my project look likep ul lichangelogtxtli liinstalltxtli lilicensetxtli lipypreprocessorpyli lireadmetxtli lisetuppyli litestpyli litodotxtli ul pemnote while a hrefhttpdocspythonorgdistutilssourcedisthtmlmanifestsdist strongdoesstrong add some files automaticallya i prefer to explicitly specify them to be sure instead of predicting what it does and doesntemp pstrongstep 2 to install the data file to the source folder modify setuppystrongp psince youre looking to add a data file licensetxt to the source install folder you need to modify the data install path to match the source install path this is necessary because by default data files are installed to a different location than source filesp pto modify the data install dir to match the source install dirp ppull the install dir info from distutils withp precodefrom distutilscommandinstall import installschemes codepre pmodify the data install dir to match the source install dirp precodefor scheme in installschemesvalues schemedata schemepurelib codepre pand add the data file and location to setup:</p> <pre><code>data_files=[('', ['license.txt'])] </code></pre> <p><em>note: the steps above should accomplish exactly what you described in a standard manner without requiring any extension libraries.</em> </p>

can i get my instance of mechanizebrowser to stay on the same page after calling bformsubmit

pthe answer to my immediate question in the headline is yes with codemechanizebrowseropennovisitcode it works just like codeopencode but it doesnt change the state of the browser instance that is it will retrieve the page and your browser object will stay where it wasp

ordering shuffled points that can be joined to form a polygon in python

pi wrote a paper on a generalization of your problem long ago there is a nice desription a hrefhttpwwwcsmcgillcacs644godfried2005fallsdroui9p0introductionhtmlherea created for a class in computational geometry the generalization is that the algorithm works even if your polygon has holes see below if it does not have holes it still works without modification br nbspnbspnbspnbspnbsp img srchttpistackimgurcombmwbbjpg altpolygon with holes br p blockquote pj orourke uniqueness of orthogonal connectthedots emcomputational morphologyem gt toussaint editor elsevier science publishers bvnorthholland 1988 99104p blockquote

convert an int to list of individual digitals more faster

pmaybe i am missing something but shouldnt this be enough without value checkingp precodedef inttolisti return intx for x in strizfill9 def listtointl return intjoinstrx for x in l codepre pstrongreferencestrong a hrefhttpdocspythonorglibrarystdtypeshtmlstrzfill relnofollowcodestrzfillcodeap

python while loop wont stop

pbecause youre using codewhile truecode and codetruecode is always equal to true so this loop will never stop you can do something like thisp precodewhile true if p1 cg2 cg2 mnmx2 guess based on middle of highest and lowest print computer has guessed d cg2 previousguessappendcg2 count21 else print the computer has guessed it in d times count2 break use break to break the loop codepre por just like thisp precodewhile p1 cg2 cg2 mnmx2 guess based on middle of highest and lowest print computer has guessed d cg2 previousguessappendcg2 count21 codepre pif codep1 cg2code is equal to false this loop will terminatedp

multivariate normal density in python

pif still needed my implementation would bep precodeimport numpy as np def pdfmultivariategaussx mu cov caculate the multivariate normal density pdf keyword arguments x numpy array of a d x 1 sample vector mu numpy array of a d x 1 mean vector cov numpy array of a d x d covariance matrix assertmushape0 gt mushape1 mu must be a row vector assertxshape0 gt xshape1 x must be a row vector assertcovshape0 covshape1 covariance matrix must be square assertmushape0 covshape0 covmat and muvec must have the same dimensions assertmushape0 xshape0 mu and x must have the same dimensions part1 1 2 nppilenmu2 nplinalgdetcov12 part2 12 xmutdotnplinalginvcovdotxmu return floatpart1 npexppart2 def testgausspdf x nparray00 mu nparray00 cov npeye2 printpdfmultivariategaussx mu cov prints 015915494309189535 if name main testgausspdf codepre pin case i make future changes the code is a hrefhttpsgithubcomrasbtpythonreferenceblobmasterusefulscriptsmultivariategaussianpdfpy relnofollowhere on githubap

python adding variable as value in a dict

pyou may either p precoded dname yourname codepre porp precoded name yourname codepre pboth would workp

prime numbers which can be written as sum of the squares of two numbers x and y

pdo not check whether each number is prime precompute all the prime numbers in the range using a hrefhttpsenwikipediaorgwikisieveoferatosthenes relnofollowsieve of eratosthenesa this will greatly reduce the complexityp psince you have maximum of 200m numbers and 256mb memory limit and need at least 4 bytes per number you need a little hack do not initialize the sieve with all numbers up to codeycode but only with numbers that are not divisible by 2 3 and 5 that will reduce the initial size of the sieve enough to fit into the memory limitp pstrongupdstrong as correctly pointed out by will ness in comments sieve contains only flags not numbers thus it requires not more than 1 byte per element and you dont even need this precomputing hackp

which python testing framework to use

pa hrefhttpnosereadthedocsorgenlatestnosea does all of this just codecdcode to the root of your tree of python files and runp precodenosetests codepre pnose a hrefhttpnosereadthedocsorgenlatestfindingtestshtmlfinds test filesa using a a hrefhttpnosereadthedocsorgenlatestwritingtestshtmlregexa basically the word codetestcode or codetestcode present in the namep blockquote pif it looks like a test its a test names of directories modules classes and functions are compared against the testmatch regular expression and those that match are considered tests any class that is a unittesttestcase subclass is also collected so long as it is inside of a module that looks like a testp blockquote

proper use of list comprehensions python

pfrom python documentationp blockquote pa hrefhttpdocspythonorgtutorialdatastructureshtml relnofollowlist comprehensions provide a concise way to create lists common applications are to make new listsap blockquote pperhaps you want to learn more about a hrefhttpdocspythonorglibraryfunctionshtmlreduce relnofollowreducea a hrefhttpdocspythonorglibraryfunctionshtmlfilter relnofollowfiltera and a hrefhttpdocspythonorglibraryfunctionshtmlmap relnofollowmapa functionsp

is something wrong with my python 332

pyou need to indent your code properlyp precodegtgtgt temperature 70 gtgtgt if temperature gt 60 and temperature lt 75 printjust right else printoh no just right codepre pemwhen you indent it properly the codecode will automatically show up so dont type those inemp punlike most languages in python indentation is important it is how the python interpreter indentifies emblocks of codeem you might hear the phrase whitespace is significant it means the same thing whitespace means things you type that dont print like spaces the tab character etcp pso you should always line up the identifier of blocks of code lines that end with codecode at the left margin it is not important how many spaces you indent the body of these blocks of code in your example the print function is in the body of the if statement as long as there is one space python will work however the standard is to use 4 spaces so better get into the habit putting four spaces whenever you want to indent codep

is there an uptodate fast yaml parser with python bindings

pthe linked wiki page states after the warning use libyaml c and pyyaml python although the note does have a bad wikilink should be codepyyamlcode not codepyyamlcodep pas for performance depending on how you installed pyyaml you should have the cparser class available which implements a yaml parser written in optimized c while i dont think this gets around the gil issue it is markedly faster here are a few cursory benchmarks i ran on my machine amd athlon ii x4 640 30ghz 8gb ramp pfirst with the default purepython parserp precode usrbinpython2 m timeit s import yaml yfilelargeyaml rread yamlloady 10 loops best of 3 405 msec per loop codepre pwith the cparserp precode usrbinpython2 m timeit s import yaml yfilelargeyaml rread yamlloady loaderyamlcloader 10 loops best of 3 592 msec per loop codepre pand for comparison with pypy using the purepython parserp precode pypy m timeit s import yaml yfilelargeyaml rread yamlloady 10 loops best of 3 101 msec per loop codepre pfor codelargeyamlcode i just googled for large yaml file and came across this p pa hrefhttpsgistgithubcomnrh667383raw1b3ba75c939f2886f63291528df89418621548fdlargeyamlhttpsgistgithubcomnrh667383raw1b3ba75c939f2886f63291528df89418621548fdlargeyamlap pi had to remove the first couple of lines to make it a singledoc yaml file otherwise yamlload complainsp peditp panother thing to consider is using the codemultiprocessingcode module instead of threads this gets around gil problems but does require a bit more boilerplate code to communicate between the processes there are a number of good libraries available though to make multiprocessing easier. there's a pretty good list of them <a href="http://wiki.python.org/moin/parallelprocessing">here</a>.</p>

sqlalchemy commit changes to object modified through dict

pthe problem does not reside in sqlalchemy but is due to pythons a hrefhttpdocspythonorg2howtodescriptorhtml relnofollowdescriptors mechanisma every codecolumncode attribute is a descriptor this is how sqlalchemy hooks the attribute retrieval and modification to produce database requestsp plets try with a simpler examplep precodeclass descobject def getself obj typenone print get def setself obj value print set class aobject desc desc a a adesc prints get adesc 2 prints set codepre phowever if you go through codeacode eminstanceem dictionary and set another value for codedesccode you bypass the descriptor protocol see a hrefhttpdocspythonorg2referencedatamodelhtmlinvokingdescriptors relnofollowinvoking descriptorsap precodeadictdesc 0 does not print anything codepre phere we just created a new eminstanceem attribute called codedesccode with a value of 0 the codedescsetcode method was never called and in your case sqlalchemy wouldnt get a chance to catch the assignmentp pthe solution is to use a hrefhttpdocspythonorg2libraryfunctionshtmlsetattr relnofollowcodesetattrcodea which is exactly equivalent to writing codeadesccodep pre><code>setattr(a, 'desc', 1) # prints '__set__' </code></pre>

easiest way to turn a list into an html table in python

pi would decompose your problem into two partsp ul ligiven a flat list produce a list of sublists where the sublists are of a given length and the overall list may be walked into either a row major order your first and third example or column major your second exampleli ligiven a list of sublists with string items produce an html table out of itli ul pi think the two tasks are really very distinct and theres nothing to gain and much to lose in mushing them up so i would be astonished if any welldesigned library did such mushingp pfor point 1 rowmajor is easyp precodedef rowmajoralist sublen return alistiisublen for i in range0 lenalist sublen codepre pand columnmajor not that badp precodedef colmajoralist sublen numrows lenalistsublen1 sublen return alistisublen for i in rangenumrows codepre pfor examplep precodel onetwothreefourfivesixseveneightnine for r in rowmajorl 3 print r print for r in colmajorl 3 print r for r in rowmajorl 4 print r codepre pproduces your three desired results one list per row not in html form yetp pthe second half of the problem produce an html table from a list of lists of stringsp precodedef htmltablelol print lttablegt for sublist in lol print lttrgtlttdgt print lttdgtlttdgtjoinsublist print lttdgtlttrgt print lttablegt;' </code></pre> <p>if you want to get it as a single string rather than print it out, change each <code>print</code> into <code>yield</code> and use <code>'\n'.join(html_table(lol))</code>.</p> <p>now you have two simple, useful, usable and reusable building blocks -- having them separate will come in handy whenever you want to present your data as anything but an html table, and also whenever the list-of-lists to present as an html table comes from any other way of building it. putting them together is easy to do in your application code, but of course it's also easy to do a simple "glue routine", e.g., assuming the <code>yield</code>-based version of <code>html_table</code> and that a single string result is desired:</p> <pre><code>def list_to_html_table(alist, sublength, column_major=false): if column_major: lol = col_major(alist, sublength) else: lol = row_major(alist, sublength) return ''.join(html_table(lol)) </code></pre> <p>isn't this building-blocks approach really nicer and more pleasant, as well as more productive, than programming in terms of big blobs of mushed-up glue...?-)</p>

when to use osname sysplatform or platformsystem

pit depends on whether you prefer raising exception or trying anything on an untested system and whether your code is so high level or so low level that it can or cant work on a similar untested system eg untested mac posix or on embedded arm systems more pythonic is to not enumerate all known systems but to test possible relevant properties eg it is considered important the endianess of the system but unimportant multiprocessing propertiesp ul liposname is a sufficient resolution for the correct usage of codeoscode module possible values are posix nt os2 ce or riscos where probably only the first two are mostly importantpli lipsysplatform is a finer resolution it is recommended to use codeif sysplatformstartswithlinuxcode idiom because linux2 means a linux kernel version 2xx or 3 older kernels are currently never used in python 33 are all linux systems simple linux pli ul pi do not know the specifics of mac and java systems and so i can not use the results of very good method platformsystem for branching but i would use advantages of the codeplatformcode module for messages and error loggingp

pandas random order of columns when writing dataframe to csv

ppython dictionaries are essentially a hrefhttpsdocspythonorg2tutorialdatastructureshtmldictionariesunorderedap pyou can explicitly order the columns like thisp precodedf dfabc codepre

how to make string indices circular when string index out of range

pyou just need to do codemystringltindexgt lenmystringcode codeltindexgtcode would be any integer that will be an indexp pfor examplep precodemystring26 lenmystring gtgtgt a codepre

does comparing using compare identities before comparing values

pfor userdefined class instances codeiscode is used as a fallback where the default codeeqcode isnt overridden codea bcode is evaluated as codea is bcode this ensures that the comparison will always have a result except in the codenotimplementedcode case where comparison is explicitly forbiddenp pthis is somewhat obliquely good spot a hrefhttpstackoverflowcomusers279627svenmarnachsven marnacha referred to in the a hrefhttpsdocspythonorg3referencedatamodelhtmlobjecthash relnofollowdata model documentationa emphasis minep blockquote puserdefined classes have codeeqcode and codehashcode methods by default with them strongall objects compare unequal except with themselvesstrong and codexhashcode returns an appropriate value such that codex ycode implies both that codex is ycode and codehashx hashycodep blockquote hr pyou can demonstrate it as followsp precodegtgtgt class unequalobject def eqself other return false gtgtgt ue unequal gtgtgt ue is ue true gtgtgt ue ue false codepre pso codeeqcode must be called before codeidcode butp pre<code>&gt;&gt;&gt; class noequal(object): pass &gt;&gt;&gt; ne = noequal() &gt;&gt;&gt; ne is ne true &gt;&gt;&gt; ne == ne true </code></pre> <p>so <code>id</code> must be invoked where <code>__eq__</code> isn't defined.</p> <hr> <p>you can see this <a href="https://hg.python.org/cpython/file/tip/objects/object.c#l679" rel="nofollow">in the cpython implementation</a>, which notes:</p> <pre class="lang-c prettyprint-override"><code>/* if neither object implements it, provide a sensible default for == and !=, but raise an exception for ordering. */ </code></pre> <p>the <em>"sensible default"</em> implemented is a c-level equality comparison of the pointers <code>v</code> and <code>w</code>, which will return whether or not they point to the same object.</p>

why this list comprehension is faster than equivalent generator expression

pi believe the difference here is entirely in the cost of 1000000 additions testing with 64bit pythonorg 330 on mac os xp precodein 698 timeit len none for n in range 1 1000000 if n3 1 10 loops best of 3 127 ms per loop in 699 timeit sum 1 for n in range 1 1000000 if n3 1 10 loops best of 3 138 ms per loop in 700 timeit sum 1 for n in range 1 1000000 if n3 1 10 loops best of 3 139 ms per loop codepre pso its not that the comprehension is faster than the genexp they both take about the same time but calling codelencode on a codelistcode is instant while summing 1m numbers adds another 7 to the total timep pthrowing a few different numbers at it this seems to hold up unless the list is very tiny in which case it emdoesem seem to get faster or large enough that memory allocation starts to become a significant factor which it isnt yet at 333kp

matplotlib change colormap after the fact

puse the codeupdatecolorscode to update the colors of all linesp precodeimport pylab as pl import numpy as np cm plgetcmaporrd x nplinspace0 1 100 def updatecolorsax lines axlines colors cmnplinspace0 1 lenlines for line c in ziplines colors linesetcolorc fig ax plsubplots for i in range10 axplotx x1i01 updatecolorsax codepre

python leaking memory while using pyqt and matplotlib

pthe pyplot interface is meant for easy interactive use but for embedding in an application the objectoriented api is better for example pyplot keeps track of all figures you have created your codeplotclosefigurecode emshouldem get rid of them but maybe it doesnt get executed try putting it inside codefinallycode or reusing the same figure objectp psee a hrefhttpmatplotlibsourceforgenetexamplesuser5finterfacesembedding5fin5fqt4htmlthis examplea of embedding matplotlib in a pyqt4 application using the objectoriented api its more work but since everything is explicit you shouldnt get memory leaks from the behindthescenes automation that pyplot doesp

wrote a function to determine if a number is a positive integer and it returns true for negative numbers

pthis all seems needlessly complicated and using codeevalcode on coderawinputcode is a security risk the user can enter anything they likep pinstead try something likep precodedef isoks try i ints except valueerror return false false else return true i gt 0 codepre pexample inputs and outputsp precodegtgtgt for s in foo 9 9 print s isoks foo false false 9 true true 9 true false codepre hr pyour error is herep precodeif x gt 0 codepre premember codexcode is still a string and in python 2x all strings will compare codegt 0codep

pygame animation using mutiple images overlappingnot working

pstrongbtwstrong your code could look like thisp pi use my images in example but there are still lines with your imagesp pi use timer to change imagesbr you can press space to pause and escape to exit p petcp precodeimport pygame class sprite def initself x y currentime selfrect pygamerectx y 100 110 selfimages for x in range12 for x in range14 img pygameimageloadball strx png img pygameimageloadcuserstrevorskydrivedocumentstest20sprite strx png selfimagesappend img selfcurrentimage 0 selftimenum 100 miliseconds selftimetarget currentime selftimenum def updateself currentime if currentime gt selftimetarget selftimetarget currentime selftimenum selfcurrentimage 1 if selfcurrentimage lenselfimages selfcurrentimage 0 def renderself window windowblitselfimagesselfcurrentimage selfrect -------------------------------------------------------- # constans - uppercase black = (0 ,0 ,0 ) white = (255,255,255) #---------------------------------------------------------------------- # main def main(): pygame.init() window = pygame.display.set_mode((800,600)) pygame.display.set_caption("test2") move_x, move_y = 0, 0 clock = pygame.time.clock() curren_time = pygame.time.get_ticks() player = sprite(110,100, curren_time) font = pygame.font.sysfont(none, 150) pause_text = font.render("pause", 1, white) pause_rect = pause_text.get_rect( center = window.get_rect().center ) # center text on screen # mainloop state_game = true state_pause = false while state_game: curren_time = pygame.time.get_ticks() # events for event in pygame.event.get(): if event.type == pygame.quit: state_game = false elif event.type == pygame.keydown: if event.key == pygame.k_escape: state_game = false elif event.key == pygame.k_space: state_pause = not state_pause if event.key == pygame.k_left: move_x = -3 elif event.key == pygame.k_right: move_x = 3 elif event.key == pygame.k_up: move_y = -3 elif event.key == pygame.k_down: move_y = 3 elif event.type == pygame.keyup: if event.key in (pygame.k_left, pygame.k_right): move_x = 0 elif event.key in (pygame.k_up, pygame.k_down): move_y = 0 # moves if not state_pause: player.rect.x += move_x player.rect.y += move_y player.update(curren_time) # draws window.fill(black) player.render(window) if state_pause: window.blit(pause_text, pause_rect) pygame.display.flip() # fps clock.tick(50) # the end pygame.quit() #---------------------------------------------------------------------- if __name__ == '__main__': main() </code></pre> <p><img src="http://i.stack.imgur.com/k6dvy.png" alt="enter image description here"></p> <p><img src="http://i.stack.imgur.com/ntj2k.png" alt="ball1.png"> ball1.png <img src="http://i.stack.imgur.com/zfoed.png" alt="ball2.png"> ball2.png <img src="http://i.stack.imgur.com/sjzut.png" alt="ball3.png"> ball3.png</p>

calculating minimum length among the lists inside a list

pa few optionsp precodea 10121113111111 311451111 11678 print mina keylen 1 1 6 7 8 print lenmina keylen 5 print minmaplen a 5 codepre

python error unsupported operand types for int and datetimetimedelta

pcodeoffsetcode is a a hrefhttpsdocspythonorg2librarydatetimehtmldatetimetimedelta relnofollowcodedatetimetimedeltacode objecta if you need just the seconds extract them with a hrefhttpsdocspythonorg2librarydatetimehtmldatetimetimedeltatotalseconds relnofollowcodetimedeltatotalsecondscodeap precodereturn utcdatetime offsettotalseconds codepre pyour emfunction signatureem however suggests it was expecting you to feed it a codedatetimedatetimecode object in which case you shouldnt change this function but the code that calls it clearly you are giving it an integer insteadp

python 27 string substitution using multiple dictionaries

pyou can use codedictdict1 dict2codep precodegtgtgt dict1 foo bar gtgtgt dict2 car vroom gtgtgt dictdict1 dict2 car vroom foo bar gtgtgt print value 1 is foos and value 2 is cars dictdict1 dict2 value 1 is bar and value 2 is vroom codepre

sqlite sqlalchemy how to enforce foreign keys

pbuilding on the answers from conny and shadowmatter heres code that will check if you are using sqlite3 before emitting the pragma statementp precodefrom sqlalchemy import event from sqlalchemyengine import engine from sqlite3 import connection as sqlite3connection eventlistensforengine connect def setsqlitepragmadbapiconnection connectionrecord if isinstancedbapiconnection sqlite3connection cursor dbapiconnectioncursor cursorexecutepragma foreignkeyson cursorclose codepre

append operation in hadoop webhdfs client

passuming your user name is codehdfscode add codeampusernamehdfscode to your url write operations require a valid user p pyour java code works because it pulls your user information from the unix environment p pif you see the user codedrwhocode anywhere its probably because you havent set a codeusernamecode in your request p

how to update mysql with python where fields and entries are from a dictionary

pyou dont want to be putting literal values in using string interpolation sql injection attacks are strongnot a good thingtmstrong instead you use the placeholder syntax relevant for your database i think mysqls is sp pemnote im using codeformatcode here change to use if you want but escape any semp precoded col1 val1 col2 val2 sql update table set format joinsformatk for k in d print sql update table set col2s col1s codepre passuming codecurcode is a db cursor the correct way to perform the query isp precodecurexecutesql dvalues codepre pthis works because although the ordering of a dictionary is effectively arbitrary order the order of keysvalues of a dict will be consistent such that codedictzipdkeys dvalues dcodep

ensure a single instance of an application in linux

pthis builds upon the a hrefhttpsstackoverflowcoma221159832230answera by user a hrefhttpsstackoverflowcomusers12138zgodazgodaa it mainly addresses a tricky concern having to do with write access to the lock file in particular if the lock file was first created by coderootcode another user codefoocode can then no successfully longer attempt to rewrite this file due to an absence of write permissions for user codefoocode the obvious solution seems to be to create the file with write permissions for everyone this solution also builds upon a different a hrefhttpsstackoverflowcoma15015748832230answera by me having to do creating a file with such custom permissions this concern is important in the real world where your program may be run by any user including coderootcodep precodeimport fcntl os stat tempfile appname myapp lt customize this value establish lock file settings lfname lockformatappname lfpath ospathjointempfilegettempdir lfname lfflags osowronly osocreat lfmode statsiwusr statsiwgrp statsiwoth this is 0o222 ie 146 create lock file regarding umask see httpsstackoverflowcoma15015748832230 umaskoriginal osumask0 try lffd osopenlfpath lfflags lfmode finally osumaskumaskoriginal try locking the file try fcntllockflffd fcntllockex fcntllocknb except ioerror msg error may already be running only one instance of it can run at a time formatappname exitmsg codepre pa limitation of the above code is that if the lock file already existed with unexpected permissions those permissions will not be correctedp pi wouldve liked to use codevarrunltappnamegtcode as the directory for the lock file but creating this directory requires coderootcode permissions you can make your own decision for which directory to usep pnote that there is no need to open a file handle to the lock filep

seaborn matplotlib how to repress scientific notation in factorplot yaxis

pit looks like the following line solves the issue p precodepltticklabelformatstyleplain axisy codepre phere is the a hrefhttpmatplotliborgapiaxesapihtmlmatplotlibaxesaxesticklabelformat relnofollowdocumentation linkap

django custom validation in model form for imagefield max file size etc

pthe name of method should be codecleanltfield namegtcode in this case codecleanbannercodep pfor future reference i will place a snippet of code that i used in one recent project names must be adapted to work with op code p precodefrom pil import image from djangoutilstranslation import ugettext as def cleanphotoself image selfcleaneddatagetphoto false if image img imageopenimage w h imgsize validate dimensions maxwidth maxheight 500 if w gt maxwidth or h gt maxheight raise formsvalidationerror please use an image that is smaller or equal to s x s pixels maxwidth maxheight validate content type main sub imagecontenttypesplit if not main image and sublower in jpeg pjpeg png jpg raise formsvalidationerrorplease use a jpeg or png image validate file size if lenimage gt 1 1024 1024 raise formsvalidationerrorimage file too large maximum 1mb else raise formsvalidationerrorcouldnt read uploaded image return image codepre

dropping a single sub column from a multiindex

pa hrefhttppandaspydataorgpandasdocsstablegeneratedpandasdataframedrophtml relnofollowdropa is a very flexible method and there are quite a few ways to use itp precodein 11 mi pdmultiindexfromproductcol1 col2 col3 a b in 12 df pddataframe1 index0 columnsmi in 13 df out13 col1 col2 col3 a b a b a b 0 1 1 1 1 1 1 codepre pdrop a single column using a tuplep precodein 14 dfdropcol1 a axis1 out14 col1 col2 col3 b a b a b 0 1 1 1 1 1 codepre por a list using a list of tuplesp precodein 15 dfdropcol1 a col2 b axis1 out15 col1 col2 col3 b a a b 0 1 1 1 1 codepre por across a level eg all codeacodesp precodein 16 dfdropa level1 axis1 out16 col1 col2 col3 b b b 0 1 1 1 codepre pemin 014 youll also be able to pass regex of what to dropemp ptheres also a way to drop the entire level of a indexcolumnp precodein 21 dfcolumnsdroplevel1 out21 indexucol1 ucol1 ucol2 ucol2 u'col3', u'col3'], dtype='object') </code></pre>

no code completion and syntax highlighting in pydev

pto enable code completion go to window preferences pydev editor code completion and check the use code completion box as well as the other boxes for what you want to complete on it seems to take a second to load the first time it has to complete somethingp psyntax coloring should just work by default rightclick on the file in the package explorer go to open with and make sure youre opening it with the python editor and not the regular text editorp pi dont know exactly what you mean by importing external modules i have my source in a separate directory structure on disk my pydev projects contain folders linked to those code completion works for that as well as other modules like os if youre having troubles are the modules added to the pydevs python search path not necessarily the same as the regular onep pi took a brief look at komodo and wingware a while back so i cant answer the second part of your question but ended up going with pydev im not a big fan of eclipse but pydev works reasonably well for mep

how do programming languages call code written in another language

ppython can be extended in cc more info a hrefhttpdocspythonorg2extendingextendinghtml relnofollowhereap pit basically means that you can wrap a c module like thisp precodeinclude pythonh static function returning a pyobject pointer static pyobject keywdargparrotpyobject self pyobject args pyobject keywds takes self args and kwargs int voltage no such thing as strings here its a tough life char state a stiff char action voom char type norwegian blue possible keywords static char kwlist voltage state action type null unpack arguments if pyargparsetupleandkeywordsargs keywds isss kwlist ampvoltage ampstate ampaction amptype return null print to stdout printf this parrot wouldnt s if you put i volts through itn action voltage printf lovely plumage the s its sn type state reference count some none pyincrefpynone return some none return pynone static pymethoddef static pymethoddef keywdargmethods the cast of the function is necessary since pycfunction values only take two pyobject parameters and keywdargparrot takes three declare the parrot function say what it takes and give it a doc string parrot pycfunctionkeywdargparrot methvarargs methkeywords print a lovely skit to standard output null null 0 null sentinel codepre pand using the python header files it will define and understand entry points and return locations in the cc codep

simple django admin app how to track file versions

pdjango never overwrites an uploaded file if you upload foopng twice the second will be foo1png i just tested this but dont take my word for it try it too p pall you have to do or let djangoreversion do is keep track of the previous file namesp

profiling self and arguments in python

pyou need to pass localsglobals dict and pass first argument what you will usually type egp precodecprofilerunctxselfprofilecommand100 globalslocals codepre puse something like thisp precodeclass aobject def performprofileself import cprofile cprofilerunctxselfprofilecommand100 globalslocals def profilecommandself a for i in xrangea pass print end aperformprofile codepre pand dont call whole ui in profile profile the specific function or computationp

can someone explain the operator to me

pthe carat codecode is bitwise xor imagine it like thisp precodegtgtgt 83 11 codepre hr precode8 in binary 1000 3 in binary 0011 83 1011 codepre

how do i remove packages installed with pythons easyinstall

pfirst you have to run this commandp precode easyinstall m package codepre pit removes all dependencies of the packagep pthen remove egg file of that packagep precode sudo rm rf usrlocallibpython2xsitepackagespackageegg codepre

python web development with or without a framework

pthe commandline python imo definitely comes first get that to work since thats the core of what youre doingp pthe issue is that using a web frameworks orm from a command line application isnt obvious django provides specific instructions for using their orm from a commandline app those are annoying at first but i think theyre a lifesaver in the long run i use it heavily for giant uploads of customersupplied filesp pdont use bare cgi its not impossible but too many things can go wrong and theyve all been solved by the frameworks why reinvent something just use someone elses codep pframeworks involve learning but no real overhead theyre not slow theyre code you dont have to write or debugp ol liplearn some pythonpli lipdo the a hrefhttpdocsdjangoprojectcomendevdjangoa tutorialpli lipstart to build a web appp pa start a django project build a small application in that projectp pb build your new model using the django orm create a django unit test for the model be sure that it works youll be able to use the default admin pages and do a lot of playing around just dont build the ementireem web site yetpli lipget your commandline app to work using django orm essentially you have to finesse the settings file for this app to work nicely see the a hrefhttpdocsdjangoprojectcomendevtopicssettingstopicssettingssettingsconfigurationa section pli liponce youve got your command line and the default admin running you can finish the web apppli ol pheres the golden rule of frameworks strongits code you dont have to write debug or maintainstrong use themp

gtkprogressbar not working in python

pthe problem is you are processing the whole directory when you are creating the window that is even before you show it in the line with codeselfdirfileslistdirpathcode it seems to me you want to call it after pressing the button applyp pthere are at least 2 possible solutions use threads or use iterators for your specific use case i think iterator would be enough besides than simpler and more pythonic i would recommend threads only when you emreallyem need themp pinstead of walking through the whole directory beforehand and the process them later you can process each file in each directory at a timep pin your example i would change the method codedirfileslistcode renamed to codewalkcode and codeonbuttonpressedcode asp pre classlangpy prettyprintoverridecodefrom gc import collect from girepository import gtk gobject codepre pwe now need to import also gobject to use codeidleaddcode which calls a callback whenever there are no higher priority events pending also once the task is finished we need to remove the callback to not call it anymore we need codesourceremovecode for thatp pi renamed your method codedirfileslistcode as codewalkcode because it seems semantically closer to an iterator when we walk through each directory and file we will temporarily return using codeyieldcode remember codeyield truecode means that there are pending items to process codeyield falsecode means we stop the iterationp pso the method would bep pre classlangpy prettyprintoverridecodedef walkself dirpath selfdirlist for root dirs files in oswalkdirpath i 00 selfsettitleospathdirnameroot for fn in files i i 10 f ospathjoinroot fn selfdirlistappendf selfprogressbarsetfractioni lenfiles collect yield true yield true gobjectsourceremoveselfid yield false codepre pnow we update the codeprogressbarcode here in this particular part i am updating the progress bar inside each directory that is it will be restarted in every subdirectory and the progress bar will restart in each of them to have an idea of which directory is visiting set the window title with the current directory the important part to understand here is codeyieldcode you can adapt this to whatever you want to dop> <p>once we have walked the whole directory, we have to return <code>yield false</code>, but before that we remove the callback (<code>gobject.source_remove(self.id)</code>).</p> <p>i consider here that <code>self.dir_list</code> is not useful here anymore, but you might have something different in mind.</p> <p>you might wonder when and how <code>walk</code> is called? that can be set when the button is pressed:</p> <pre><code>def on_button_pressed(self, button, *args): homedir = os.path.expanduser('~') rootdir = os.path.join(homedir, 'documents') self.task = self.walk(rootdir) self.id = gobject.idle_add(self.task.next) </code></pre> <p><code>self.task</code> is an iterator, which has the method <code>next()</code> that retrieves the next item from <code>self.task</code>, which is going to be called whenever there are no pending events (with <code>idle_add</code>). we get the <code>id</code> in order to remove the callback once we are done.</p> <p>you have to remove the line <code>self.dir_files_list(dir_path)</code> from the <code>__init__</code> method.</p> <p>one more thing: i called the garbage collector manually (<code>gc.collect()</code>) because it could be useful when processing a large directory (depending on what you are doing with them).</p>

how do i get intellij to recognize common python modules

pjust create and add python sdkp precodefile gt project structure gt project gt project sdk gt new codepre pand select the installation path of your python interpreter for example codecpython26code in windows and codeusrbinpython27code in linux as the home pathp prelated discussion a hrefhttpdevnetjetbrainsnetthread286883httpdevnetjetbrainsnetthread286883ap

splitting a string into an iterator

pnot directly splitting strings as such but the coderecode module has a hrefhttpdocspythonorg2libraryrehtmlrefinditer relnofollowcoderefinditercodea and corresponding codefinditercode method on any compiled regular expressionp pzero asked for an examplep precodegtgtgt import re gtgtgt s the quick brownnfox gtgtgt for m in refinditers s printmspan mgroup0 0 3 the 4 9 quick 13 18 brown 19 22 fox codepre

convert letters to lower case

pas oxtopus suggested you can simply convert letters to their lowercase version with codetextlowercode no need for a regular expression this works with unicode strings too   etcp

dictionary with list of values

puse a a hrefhttpdocspythonorglibrarycollectionshtmlcollectionsdefaultdictcodedefaultdictcodea to calculate the sumsp precodefrom collections import defaultdict res defaultdictint with openfootxt r as f for line in f kv linesplit resk intv res is now a 12 b 5 c 8 codepre pif you dont want the sums but lists of elements modify that top precodefrom collections import defaultdict res defaultdictlist with openfootxt r as f for line in f kv linesplit reskappendv res is now a 1 2 9 b 5 c 8 codepre pnote that i changed some variable names notable codefilecode to codefcode and codedictcode to coderescode thats because codefilecode and codedictcode are the names of builtins and should therefore be avoided as variable names in order to avoid confusionp palso codereadlinescode is not necessary you can directly iterate over the filep padditionally the a hrefhttpdocspythonorgreferencecompoundstmtshtmlthewithstatementcodewithcodea statement ensures that the file gets closed afterwardsp

trouble getting if statement to work in def but not in interpreter

precodedef tests n sfindnot b sfindbad if n lt b return sreplacesn good print testthis dinner is not that bad codepre pyou should codereturncode the result from function codetestcodep

python add list to set

psets cant have mutable changeable elementsmembers a list being mutable cannot be a member of a setp pas sets are mutable you cannot have a set of sets you can have a set of frozensets thoughp pthe same kind of mutability requirement applies to the keys of a dictp pother answers have already given you code i hope this gives a bit of insight im hoping alex martelli will answer with even more detailsp

avoid escaping glob expressions in plumbum

blockquote pbut is there a way to make it understand glob expressions should be passed to the shell asisp blockquote pcodeplumbumcode passes codeacode to codelscode command asis codelscode command doesnt run any shell so there is no glob expansion it is done by the shell on nixp pyou could use codeglobcode module to do the expansionp precodefrom glob import glob lsl globa codepre panother way is to use codeworkdircode objectp precodefrom plumbum import local lsl localcwd a codepre pto defer the call you could use codelslargscode syntax note there is probably a bug in codeplumbum 110code version that requires to convert codeargscode list to a tuple explicitlyp pif you want you could call the shellp precodefrom plumbumcmd import sh shc ls l a codepre pnote pythons codeglobglobcode function might produce the glob expansion different from that of the shellp

sort numpy string array with negative numbers

pyou could use a hrefhttpnedbatcheldercomblog200712humansortinghtmlnatural sortingap precodeimport numpy as np import re def atoitext try return inttext except valueerror return text def naturalkeystext alistsortkeynaturalkeys sorts in human order httpnedbatcheldercomblog200712humansortinghtml return atoic for c in resplitd text a nparray3 2 1 0 2 word printsortedakeynaturalkeys 2 1 0 2 3 word a nparray3 2 1 0 2 word 1 word 2 up printsortedakeynaturalkeys 2 2 up 1 1 word 0 2 3 word codepre

why is numpy slower than python how to make code perform better

precodeimport time numpy def d a range100000 b range0100000010 c ij for ij in zipab return c def e a numpyarrayrange100000 b numpyarrayrange0100000010 c ab return c python 004s 004s 004s numpy 002s 002s 002s codepre ptry it with bigger arrays even with the overhead of creating arrays numpy is much fasterp

how to catch the error in each time in python

pyou will want to move your codetry exceptcode within your codeforcode loop if you want to continue with the ones that dont fail such as belowp precodefor progstopclock progstartclock programid in iziplongestselfprogramstopclock programstartclock progidlist fillvalue try currenttime inttimestrftimem programstoptime timestrptimeprogstopclock imp programfinished progstopclocksplit1replacepm replaceam if programstoptime epgtime1 if programfinished 00 if programwidth gt 342 programswidth 342 selfgetcontrolintprogramidsetwidthprogramswidth selfgetcontrolintprogramidsetvisiblefalse selfgetcontrolintprogramidsetpositionintposx 350 intposy selfgetcontrolintnextprogramsetposition375 intposy except valueerror e do something or ignore error codepre

opencv python matchtemplate function with multiple matches

pheres howp precoderesult cv2matchtemplateimgtemplatecvcvtmsqdiff the get the best match fast use this minxmaxyminlocmaxloc cv2minmaxlocresult xy minloc get all the matches result2 npreshaperesult resultshape0resultshape1 sort npargsortresult2 y1 x1 npunravelindexsort0 resultshape best match y2 x2 npunravelindexsort1 resultshape second best match codepre pthis is note the fastest way as the above sorts all the matches even the totally wrong ones if the performance matters to you you can use the bottlenecks a hrefhttpberkeleyanalyticscombottleneckreferencehtmlbottleneckpartsort relnofollowpartsorta function insteadp

pagination with the python cmd module

pthe simple thing would just be to pipe your script through less or a similar command at runtimep pheres a simple method that does approximately what you want thoughp precodedef printandwaitsomelongmessage lines somelongmessagesplitn i0 while i lt lenlines print njoinlinesii10 rawinputpress enter to read more i 10 codepre pyou could also look into using cursesp

looking for a nicer python syntax to pass multiple parameters to a singleparametered lambda

preplacing the lambda altogether is the usecase for codeoperatoritemgettercodep precodesortedditems keyoperatoritemgetter1 codepre

are these two python forloops the same thing

pno thats not the same p pyour version creates a new dictionary object each iteration with just one key and value the version in the video creates emoneem dictionary object with a series of keyvalue pairsp pthe version in the video is equivalent top precoded for m in months dm3lower m codepre pbut is using a a hrefhttpsdocspythonorg2tutorialclasseshtmlgeneratorexpressions relnofollowemgenerator expressionema to produce the keyvalue pairs as tuples in a loop instead the codedictcode object takes each such pair and adds them to the dictionary being constructedp pand in python 27 and newer could also be written with a a hrefhttpsdocspythonorg2tutorialdatastructureshtmldictionaries relnofollowdictionary comprehensionap precodem3lower m for m in months codepre pthe end result is a dictionary with the first three letters of each month lowercased as the keyp precodegtgtgt import calendar gtgtgt months calendarmonthname1 gtgtgt m3lower m for m in months mar march feb february aug august sep september apr april jun june jul july jan january may may nov november dec december oct october'} &gt;&gt;&gt; pprint(_) {'apr': 'april', 'aug': 'august', 'dec': 'december', 'feb': 'february', 'jan': 'january', 'jul': 'july', 'jun': 'june', 'mar': 'march', 'may': 'may', 'nov': 'november', 'oct': 'october', 'sep': 'september'} </code></pre>

extending a c application with embedded scripting

pif you want to use python i would definitely suggest using a hrefhttpwwwboostorgdoclibs1480libspythondoc relnofollowboostpythona it is an incredibly well designed library just an example all you have to do to expose a c class to python is thisp precodestruct world void setstdstring msg thisgtmsg msg stdstring greet return msg stdstring msg boostpythonmodulehello classltworldgtworld defgreet ampworldgreet defset ampworldset codepre pit handles almost everything automatically conversions between types exceptions it even allows you to use reference counted objects between the two languages with codeboostsharedptrcode p

how to handle multiple members of a c class simultaneously

pyou can do the same in c by using pointers or reference to your objectsp pif your class is codemyclasscode you could declarep precodestdvectorltmyclassgt list codepre pthen add your objects to the listp precodelistpushbackampobjectofmyclass for all of your objects codepre pand finallyp precodestdvectorltmyclassgtiterator itr for itr listbegin itr listend itr itrgtmymethod codepre pi have used codestdvectorcode for simplicity in allocating objects it grows automatically and to get an iterator which should be known to you but you could do the same just by using a plain array if you preferp

how to get the absolute path relative to the project root without double slashes

pin my django projects im using unipath it is simplifying a lot try to use a hrefhttpspypipythonorgpypiunipath10 relnofollowhttpspypipythonorgpypiunipath10a it is really nice and self explainingp

how can i get the progressdialog to close before i open my messagebox

pi think infinity77 has the right answer here people forget that gui calls are not synchronous they arent finished by the time they return that done call sends a message to the window and in response to that the window probably queues up several more messages to clean itself up when you fire up a model message box that creates its own message loop while leaving the original message loop in suspended animation thus the cleanup messages cannot be processed until the message box returns and your main message loop runs again a yield call will allow those queued up messages to drainp

python print the sum of items in list whose total is the largest and is odd

pin a easy way sum all and subtract the minimum odd number if first sum is even p precodeif suml2 1 printsuml else printsuml i for i in sortedl if i210 codepre

why is my python output delayed to the end of the program

pits because codesysstdoutcode is buffered use codeflushcodep precodeimport sys from time import sleep for i in range3 sysstdoutwrite sysstdoutflush sleep1 printwelcome codepre

how to programmatically get the md5 checksum of amazon s3 file using boto

pit seems well established that the etag is not the md5sum if the file was assembled after running a multipart upload i think in that case ones only recourse is to download the file and perform a checksum locally if the result is correct the s3 copy must be good if the local checksum is wrong the s3 copy may be bad or the download might have failed if you no longer have the original file or a record of its md5sum i think youre out of luck it would be great if the md5sum of the assembled file were available or if there were a way to locally compute the expected etag of a file to be uploaded via multipartp

differences of scipyspatialkdtree in python 27 and 35

pin python3 codezipcode returns an a hrefhttpsdocspythonorg3libraryfunctionshtmlzip relnofollowiterator objecta rather than a list of tuples codepointscode will therefore be a 0dimensional codenpobjectcode array containing a codezipcode iterator rather than a 2d array of x y coordinatesp pyou could construct a codelistcode from the iteratorp precodepoints nparraylistzipstopsstoplatstopsstoplon codepre phowever a more elegant solution might be to avoid using codezipcode altogether by indexing multiple columns of your dataframep precodepoints stopsstoplatstoplonvalues codepre

namedtuple in numpy

pa structured array like codepointtypecode does not define math operations that involve several fieldsp pwith the sample from a hrefhttpstackoverflowcoma33455682901925httpstackoverflowcoma33455682901925ap precodein 470 pointtype x float y float in 471 points nparray12 34 56 dtypepointtype in 472 points out472 array10 20 30 40 50 60 dtypex ltf8 y ltf8 in 473 points0points1 typeerror unsupported operand types for numpyvoid and numpyvoid codepre pinstead i can create a 2d array and then view it as codepointtypecode the databuffer layout will be the samep precodein 479 points nparray12 34 56float in 480 points out480 array 1 2 3 4 5 6 in 481 pointsviewpointtype out481 array10 20 30 40 5.0, 6.0)]], dtype=[('x', '&lt;f8'), ('y', '&lt;f8')]) in [482]: points.view(point_type).view(np.recarray).x out[482]: array([[ 1.], [ 3.], [ 5.]]) </code></pre> <p>i can do math across rows, and continue to view the results as points:</p> <pre><code>in [483]: (points[0]+points[1]).view(point_type).view(np.recarray) out[483]: rec.array([(4.0, 6.0)], dtype=[('x', '&lt;f8'), ('y', '&lt;f8')]) in [484]: _.x out[484]: array([ 4.]) in [485]: points.sum(0).view(point_type) out[485]: array([(9.0, 12.0)], dtype=[('x', '&lt;f8'), ('y', '&lt;f8')]) </code></pre> <p>alternatively i could start with the <code>point_type</code>, and view it as 2d for the math, and then view-it-back</p> <pre><code>pdt1=np.dtype((float, (2,))) in [502]: points out[502]: array([(1.0, 2.0), (3.0, 4.0), (5.0, 6.0)], dtype=[('x', '&lt;f8'), ('y', '&lt;f8')]) in [503]: points.view(pdt1) out[503]: array([[ 1., 2.], [ 3., 4.], [ 5., 6.]]) in [504]: points.view(pdt1).sum(0).view(point_type) out[504]: array([(9.0, 12.0)], dtype=[('x', '&lt;f8'), ('y', '&lt;f8')]) </code></pre> <p>so it is possible to view and operate on an array as 2d and as recarray. to be pretty or useful it probably needs to be burried in a user defined class.</p> <p>another option to crib ideas from the <code>recarray</code> class. at its core it is just a structured array with a specialized <code>__getattribute__</code> (and setattribute) method. that method first trys the normal array methods and attributes (e.g. <code>x.shape</code>, <code>x.sum</code>). then it tries to fine <code>attr</code> in the defined fieldnames.</p> <pre><code>def __getattribute__(self, attr): try: return object.__getattribute__(self, attr) except attributeerror: # attr must be a fieldname pass fielddict = ndarray.__getattribute__(self, 'dtype').fields try: res = fielddict[attr][:2] except (typeerror, keyerror): raise attributeerror("record array has no attribute %s" % attr) return self.getfield(*res) ... </code></pre> <p><code>points.view(np.recarray).x</code> becomes <code>points.getfield(*points.dtype.fields['x'])</code>.</p> <p>an alternate approach would be to borrow from <code>namedtuple</code> (<code>/usr/lib/python3.4/collections/__init__.py</code>), and define <code>x</code> and <code>y</code> properties, which would index the <code>[:,0]</code> and <code>[:,1]</code> columns of the 2d array. it may be easiest to add those properties to a subclass of <code>np.matrix</code>, letting that class ensure that most math results are 2d.</p>

looking for a more elegant solution to this

pthe thing i like most about python is that it makes it so easy to break a problem apartp precodedef skip67seq skipping false for value in seq skipping skipping or value 6 yield 0 if skipping else value skipping skipping and value 7 def sum67seq return sumskip67seq gtgtgt sum671 2 2 5 gtgtgt sum671 2 2 6 99 99 7 5 gtgtgt sum671 1 6 7 2 4 codepre

why use a flat list in heapsort

pyou should take a look at it you will find a lot of important thing about the sorting algorithms a hrefhttpenwikipediaorgwikisortingalgorithm relnofollowsortingap pon the other hand a hrefhttpenwikipediaorgwikiheap28datastructure29 relnofollowheapa is a treebased data structure with special properties in case of maximum heap the greatest element is in the root node and if b is a child node of a then keya keyb br heaps are crucial in several efficient graph algorithms such as a hrefhttpenwikipediaorgwikidijkstra27salgorithm relnofollowdijkstras algorithma and in the sorting algorithm a hrefhttpenwikipediaorgwikiheapsort relnofollowheapsortabr you should also check out a hrefhttpstackoverflowcomquestions8938375anintuitiveunderstandingofheapsortthisa about heap sortbr strongeditstrong pythonrelated implementation of heap sort can be found a hrefhttpbloggnucomcc2010heapsortinpython relnofollowhereap

how to get this simple python 2 code to work in python 3

pin python 3 print should be used as a function not a statement so the last line in your outer loop body needs to be codeprintcode not codeprintcode p

how can i send an email based on a new primary key being generated through django

puse a hrefhttpsdocsdjangoprojectcomendevtopicssignals relnofollowdjango signalsap precodefrom djangodbmodels import signals def sendemailonneworderinstance created raw kwargs fixtures or updates are not interesting if not created or raw return instance is your purchaseorder instance email emailmessagepurchase order system your message here toyouremailgmailcom emailsend signalspostsaveconnectsendemailonneworder senderpurchaseorder dispatchuidsendemailonneworder codepre pyou have to paste this code somewhere it will be executed during loading django eg codemodelspycodep pexample codemodelspycodep precodefrom djangocoremail import emailmessage from djangodb import models from djangodbmodels import signals class purchaseordermodelsmodel product modelscharfieldmaxlength256 vendor modelscharfieldmaxlength256 dollaramount modelsfloatfield itemnumber modelsautofieldprimarykeytrue def sendemailonneworderinstance created raw kwargs fixtures or updates are not interesting if not created or raw return instance is your purchaseorder instance email emailmessagepurchase order system your message here toyouremailgmailcom emailsend signalspostsaveconnectsendemailonneworder senderpurchaseorder dispatchuidsendemailonneworder codepre

term document matrix and cosine similarity in python

pmay i recommend you take a look at a hrefhttpscikitlearnorgstablemodulesfeatureextractionhtmlcommonvectorizerusagescikitlearna this is a very well regarded library in the python community with a very simple a consistent api they have also implemented a a hrefhttpscikitlearnorg013modulesmetricshtmlcosine similaritya metric this is an example taken from a hrefhttpstackoverflowcomquestions8897593similaritybetweentwotextdocumentsherea of how you could do it in 3 lines of codep precodegtgtgt from sklearnfeatureextractiontext import tfidfvectorizer gtgtgt vect tfidfvectorizermindf1 gtgtgt tfidf vectfittransformid like an apple an apple a day keeps the doctor away never compare an apple to an orange i prefer scikitlearn to orange gtgtgt tfidf tfidfta array 1 025082859 039482963 0 025082859 1 022057609 0 039482963 022057609 1 026264139 0 0 026264139 1 codepre

how can i wrap a block in jinja2

pyou should be able check the contents of a block using the codeselfblocknamecode syntaxp precode if selfheadline is not empty write out headline html wrapper here endif codepre pto quote from a hrefhttpjinjapocooorgdocstemplateschildtemplate relnofollowthe documentationap blockquote pif you want to print a block multiple times you can however use the special self variable and call the block with that namep blockquote precodelttitlegt block title endblock lttitlegt lth1gt selftitle lth1gt block body endblock codepre

multithreaded file read python

peach thread runs your function independently each copy of the function opens the file as a local which is not shared each python file object tracks reading state completely independently each has their own oslevel file handle herep pso no if emnothing else is altering the file contentsem each thread will see each line just once just the same as if separate emprocessesem tried to read the filep

no module named urls

pi cant reproduce the import error on my machine using your project files windows 7 django 111 python 264 everything imported fine but the urls were not specified properly like the tutorial shows fixing the codep pmysiteurlspyp precodefrom djangoconfurlsdefaults import from djangocontrib import admin adminautodiscover urlpatterns patterns rpolls includemysitepollsurls radmin includeadminsiteurls codepre pmysitepollsurlspyp precodefrom djangoconfurlsdefaults import urlpatterns patternsmysitepollsviews r index rpltpollidgtd detail rpltpollidgtdresults results rpltpollidgtdvote vote codepre pvisit a hrefhttp1270018000pollshttp1270018000pollsa i received a templatedoesnotexist exception because the template file is missingp pstrongim afraid my answer might be to reboot and try it again strongp

how to mount a network directory using python

pid recommend you use codesubprocesscheckcallcodep precodefrom subprocess import most simply checkcall mkdir mntdatadir shelltrue checkcall mount t whatever datadir mntdatadir shelltrue more securely from ospath import expanduser checkcall mkdir expanduser mntdatadir checkcall mount t whatever datadir expanduser mntdatadir codepre

pythonway of getting a substring with a specified delimiter

pyou can use the codeglobcode modulep precodeimport glob for filename in globiglob username description filenamesplit codepre

removing tuples from a list

pthe coderemovecode method takes an object to remove from the list not an index you could either use codedelcode which does take an index or pass the tuple to coderemovecode directlyp precodedef filtersent for tuple in sent if tuple1 none del sentsentindextuple sentremovetuple codepre phowever this still wont work youre modifying the list while iterating over it which will screw up your position in the iteration also both codeindexcode and coderemovecode are slow and its a bad idea to name a function codefiltercode hiding the builtin codefiltercode function it would most likely be better to create a new filtered list with a list comprehensionp precodedef filteredsent return item for item in sent if item1 none codepre

windows python version and vc redistributable version

ol liwindows python versionli lidll nameli livc redistributableli lilink to installerli ol hr ol li24 25 32 bitli limsvcr71dll msvcp72dllli limicrosoft visual c 2003 71 included with net 11li lia hrefhttpmsdnmicrosoftcomenusnetframeworkaa569264httpmsdnmicrosoftcomenusnetframeworkaa569264ali ol hr ol li26 27 30 31 32 32 bitli limsvcr90dll msvcp90dllli limicrosoft visual c 2008 redistributable package x86li lia hrefhttpwwwmicrosoftcomdownloadendetailsaspxdisplaylangenampid29httpwwwmicrosoftcomdownloadendetailsaspxdisplaylangenampid29ali ol hr ol li25 64 bitli limsvcrtdll msvcp60dllli liincluded with windowsli linali ol hr ol li26 27 30 31 32 64 bitli limsvcr90dll msvcp90dll li limicrosoft visual c 2008 redistributable package x64li lia hrefhttpwwwmicrosoftcom/download/en/details.aspx?id=15336">http://www.microsoft.com/download/en/details.aspx?id=15336</a></li> </ol>

how to change all characters except for the two

pyou just need to specify a group of characters you emdontem want to matchp precodegtgtgt resubio a flagsrei i o i o o o i codepre phere all characters except for codeicode codeocode and code code are replaced by a hyphen ignoring case placing characters inside a group prefixed with the codecode symbol means that those characters will be omitted from the matchingp

converting operator to python3

pits a synonym for the inequality operator codecode as seen in basicp pby the way the line you are asking about would be far more idiomatically written asp precodeif in tag codepre

how would you implement a basic eventloop

pi would use a simple lightweight messaging library called zeromq a hrefhttpwwwzeromqorghttpwwwzeromqorga it is an open source library lgpl this is a very small library on my server the whole project compiles in about 60 seconds p pzeromq will hugely simplify your eventdriven code and it is also the most efficient solution in terms of performance communicating between threads using zeromq is much faster in terms of speed than using semaphores or local unix sockets zeromq also be a 100 portable solution whereas all the other solutions would tie your code down to a specific operating system p

indexing the datetime column in the csv file using pandas

pif i understand your question correctly thats how you can do itp precodefrom pandas import codepre pread in the data index by matchdatep precodeframereadcsvdatescsv parsedates true indexcol 4 print frame country player runs scorerate weekday matchdate 20100216 afghanistan mohammad shahzad 118 9752 tue 20100316 india schin 112 9802 wed codepre pdefine two datetime objects that define the range that you want slicep precodexdatetime2010 1 5 ydatetime2010 2 25 codepre pand slice it get all rows that have a codematchdatecode between codexcode and codeycodep precodeprint frameixxy country player runs scorerate weekday matchdate 20100216 afghanistan mohammad shahzad 118 9752 tue codepre pif you just want to get a certain month or year you can just do thisp pcodeframeix20102codep precode country player runs scorerate weekday matchdate 20100216 afghanistan mohammad shahzad 118 9752 tue codepre

how do i find if an int is in array of arrays

precodegtgtgt a 123 456 gtgtgt print any3 in b2 for b in a false gtgtgt a 137 456 gtgtgt print any3 in b2 for b in a true codepre

python regular expressions two character contain

pi think strongpositive lookaheadstrong might be your solution herep ptested and workingp precode6 codepre pive tried it at a hrefhttpsregex101compython relnofollowregex101coma which you might also find helpful while testing your regular expressionsp

append columns of data

pthe indentation is wrong so you are writing the entire array t on every iteration instead of only at the end change it to thisp precodet for line in freadlines line linesplitt tappendssn line0 line3 f1writelinest codepre palternatively you could write the lines one at a time instead of waiting until the end then you dont need the array codetcode at allp precodefor line in freadlines line linesplitt s ssn line0 line3 f1writes codepre

importerror at no module named urls

pin your settingspy file make sure the rooturlconf is correctp pit should look something likep precoderooturlconf ltinsert project namegturls codepre pjudging by what youve provided you might want to make sure it looks likep precoderooturlconf projectnameurls codepre

how do you submit a form to an app engine python application without refreshing the sending page

psounds like you want to look into ajax the simplest way to do this is probably to use the ajax functions in one of the popular javascript libraries like jqueryp

generating random sentences from custom text in pythons nltk

pyou should be training the markov model with multiple sequences so that you accurately sample the starting state probabilities as well called pi in markovspeak if you use a single sequence then you will always start in the same statep pin the case of orwells 1984 you would want to use sentence tokenization first nltk is very good at it then word tokenization yielding a list of lists of tokens not just a single list of tokens and then feed each sentence separately to the markov model this will allow it to properly model sequence starts instead of being stuck on a single way to start every sequencep

how to check what os am i running on in python

precodegtgtgt import platform gtgtgt platformsystem codepre

check if header exists with python pandas

pcsvsniffer has a hasheader function that should return true if the first row appears to be a header a procedure for using it would be to first remove all empty rows from the top until the first nonempty row and then run csvsnifferhasheader my experience is that the header must be in the first line for hasheader to return true and it will return false if the number of header fields do not match the number of data fields for at least one row in its scan range which must be set by the user 1024 or 2048 are typical scan ranges i tried to set it much higher even so the entire file would be read but it still failed to recognize the header if it was not in the first line all my testing was done using python 2710p phere is an example of using csvsniffer in a script that first determines if a file has a recognizable header and if not renames it creates a new empty file with the original name then opens the renamed file for reading and the new file for writing and writes the renamed file contents to the new file excluding leading blank lines finally it retests the new file for a header to determine if removing the blank lines made a differencep precodeimport csv from datetime import datetime import os import re import shutil import sys import time commondelimeters set t def snifffilepath with openfilepath rb as csvfile dialect csvsniffersniffcsvfileread2048 delimiter reprdialectdelimiter if delimiter not in commondelimeters print filepathhas uncommon delimiterdelimiter else print filepathhas common delimiterdelimiter csvfileseek0 if csvsnifferhasheadercsvfileread2048 print filepath has a header return true else print filepath does not have a header return false def removeleadingblanksfilepath test filepath for header and delimiter print testingfilepathwith sniffer hasheader snifffilepath if hasheader print no need to remove leading blank lines if any infilepath return true make copy of filepath appending current datetime to its name if ospathisfilefilepath now datetimenowstrftimeydmhms m researchrazaz09zfilepath bakpath if m none bakpath filepathreplacemgroup1 now mgroup1 else bakpath filepath now try print renaming filepathto bakpath osrenamefilepath bakpath except print renaming operation failed sysexcinfo0 return false print creating a newfilepathfrombakpathminus leading blank lines now open renamed file and copy it to original filename except for leading blank lines timesleep2 try with open(bakpath) as o, open (filepath, 'w') as n: p = false for line in o: if p == false: if line.rstrip(): n.write(line) p = true else: continue else: n.write(line) except ioerror as e: print 'file copy operation failed: %s' % e.strerror return false print 'testing new',filepath,'with sniffer' has_header = sniff(filepath) if has_header: print 'the header problem with',filepath,'has been fixed' return true else: print 'the header problem with',filepath,'has not been fixed' return false </code></pre> <p>given this csv file where the header is actually on line 11:</p> <pre><code>header,better,leader,fodder,blather,super 1,2,3,,, 4,5,6,7,8,9 3,4,5,6,7, 2,,,,, </code></pre> <p>remove_leading_blanks() determined that it did not have headers, then removed the leading blank lines and determined that it did have headers. here is the trace of its console output:</p> <pre><code>testing test1.csv with sniffer... test1.csv has uncommon delimiter '\r' test1.csv does not have a header renaming test1.csv to test1.20153108142923.csv creating a new test1.csv from test1.20153108142923.csv minus leading blank lines testing new test1.csv with sniffer test1.csv has common delimiter ',' test1.csv has a header the header problem with test1.csv has been fixed done ok </code></pre> <p>while this may work a lot of the time, generally it does not appear reliable due to too much variation in headers and their placement. however, maybe its better than nothing.</p> <p>see <a href="https://docs.python.org/2/library/csv.html#csv.sniffer" rel="nofollow">csv.sniffer</a>, <a href="https://github.com/python/cpython/blob/master/lib/csv.py" rel="nofollow">csv.py</a> and <a href="https://github.com/python/cpython/blob/master/modules/_csv.c" rel="nofollow">_csv.c</a> for more info. <a href="https://pymotw.com/2/csv/" rel="nofollow">pymotw's csv – comma-separated value files</a> has a good tutorial review of the csv module with details on dialects.</p>

cant call my class in python

pby the example you gave it seems that you are only creating the new instance but not calling the codeeditinputfilecode method try to dop precodefe fileeditora b feeditinputfile codepre

update new django and python 27 with virtualenv on dreamhost with passenger

pi currently have private server a shell account and a bit of luck so here is what i dop ol lipssh to your host to upgrade pythonp precode cd mkdir tmp cd tmp wget httpwwwpythonorgftppython273python273tgz tar zxvf python273tgz cd python273 configure enableshared prefixhomepython27 enableunicodeucs4 make make install codepreli lipconfigure system to use our new python open bashrc and add the following linep precode export pathhomepython27binpath export ldlibrarypathhomepython27lib save it and run source bashrc codepre pyou can now check your python version with codewhich pythoncodepli lipinstall codeeasyinstallcode codepipcodep precodecd tmp wget httppeaktelecommunitycomdistezsetuppy python ezsetuppy easyinstall pip codepreli lipinstall codevirtualenvcodep precode pip install virtualenv virtualenv homeltsitegtenv switch to virtualenv source homeltsitegtenvbinactivate codepre pyou can also add env path to codebashrccodep precode export pathhomeltsitegtenvbinpath source bashrc codepreli lipinstall django and everything elsep precode pip install django pip install . pip install .... pip install .... </code></pre></li> <li><p>create project</p> <pre><code> cd $home/&lt;site&gt;/ python $home/&lt;site&gt;/env/bin/django-admin.py startproject project </code></pre></li> <li><p>create <code>passenger_wsgi.py</code> in <code>home/&lt;site&gt;/</code> with following content</p> <pre><code> import sys, os cwd = os.getcwd() sys.path.append(cwd) sys.path.append(cwd + '/project') #you must add your project here or 500 #switch to new python #you may try to replace $home with your actual path if sys.version &lt; "2.7.3": os.execl("$home/&lt;site&gt;/env/bin/python", "python2.7.3", *sys.argv) sys.path.insert(0,'$home/&lt;site&gt;/env/bin') sys.path.insert(0,'$home/&lt;site&gt;/env/lib/python2.7/site-packages/django') sys.path.insert(0,'$home/&lt;site&gt;/env/lib/python2.7/site-packages') os.environ['django_settings_module'] = "project.settings" import django.core.handlers.wsgi application = django.core.handlers.wsgi.wsgihandler() </code></pre></li> </ol> <p>or this way</p> <pre><code>import sys, os base_dir = os.path.dirname(os.path.abspath(__file__)) sys.path.append(os.path.join(base_dir)) #you must add your project here or 500 #switch to new python #you may try to replace $home with your actual path python_path = os.path.join(base_dir, 'env', 'bin', 'python') if sys.executable != python_path: os.execl(python_path, "python2.7.12", *sys.argv) </code></pre> <p>if you are using django 1.7, replace the last two line with</p> <pre><code>from django.core.wsgi import get_wsgi_application application = get_wsgi_application() </code></pre> <ol start="8"> <li>enjoy :d</li> </ol>

how do you filter pandas dataframes by multiple columns

pusing codeampcode operator dont forget to wrap the substatements with codecodep precodemales dfdfgendermale amp dfyear2014 codepre pto store your dataframes in a codedictcode using a for loopp precodefrom collections import defaultdict dic for g in male female dicgdefaultdictdict for y in 2013 2014 dicgydfdfgenderg amp dfyeary store the dataframes to a dict of dict codepre h2edith2 pa demo for your codegetdfcodep precodedef getdfdic gender year return dicgenderyear print gendfdic male 2014 codepre

python add list to set

pyoull want to use tuples which are hashable you cant hash a mutable object like a listp precodegtgtgt a setabcde gtgtgt a seta c b e d gtgtgt t f g gtgtgt aaddt gtgtgt a seta c b e d f g codepre

how to write a python function that adds all arguments

pjust use the a hrefhttpdocspythonorglibraryfunctionshtmlsumsuma builtin functionp precodegtgtgt def myfuncargs return sumargs gtgtgt myfunc1234 10 gtgtgt codepre hr pstrongeditstrongp pi dont know why you want to avoid sum but a hrefhttpdocspythonorglibraryfunctionshtmlreducehere we goap precodegtgtgt def myfuncargs return reducelambda x y x y args gtgtgt myfunc1234 10 gtgtgt codepre pinstead of the codelambdacode you could also use a hrefhttpdocspythonorglibraryoperatorhtmloperatoraddoperatoraddap hr pstrongedit2strongp pi had a look at your a hrefhttpstackoverflowcomquestions11519787howtofindthelistinalistoflistswhosesumofelementsisthegreatestothera a hrefhttpstackoverflowcomquestions11520087howtouseacustomfunctioninmaxxkeycustomfunctionfunction/">questions</a>, and it seems your problem is using <code>sum</code> as the <code>key</code> parameter for <code>max</code> when using a custom class. i <a href="http://stackoverflow.com/a/11521976/142637">answered</a> your question and provided a way to use your class with <code>sum</code> in my answer.</p>

read mat files in python

pive screwed half an hour even after reading the answers hope this answer helpsp pfirst save the mat file asp precodesavetestmatv7 codepre pafter that in python use the usual loadmatp precodeimport scipyio as sio test sioloadmattestmat codepre