# Python Programming/Self Help

This book is useful for learning Python, but there might be a topic that
the book does not cover. You might want to search for modules in the
standard library, or inspect an unknown object\'s functions, or perhaps
you know there is a function that you have to call inside an object but
you don\'t know its name. This is where the interactive help comes into
play.

## Built-in help overview

Built-in interactive help at a glance:

``` python
help()      # Starts an interactive help
help("topics")  # Outputs the list of help topics
help("OPERATORS") # Shows help on the topic of operators
help("len")    # Shows help on len function
help("re")    # Shows help on re module
help("re.sub")  # Shows help on sub function from re module
help(len)     # Shows help on the object passed, the len function
help([].pop)   # Shows help on the pop function of a list
dir([])      # Outputs a list of attributes of a list, which includes functions
import re
help(re)     # Shows help on the help module
help(re.sub)   # Shows help on the sub function of re module
help(1)      # Shows help on int type
help([])     # Shows help on list type
help(def)     # Fails: def is a keyword that does not refer to an object
help("def")    # Shows help on function definitions
```

## Navigating Help

To start Python\'s interactive help, type \"help()\" at the prompt.

`>>>help()`

You will be presented with a greeting and a quick introduction to the
help system. For Python 2.6, the prompt will look something like this:

`Welcome to Python 2.6! This is the online help utility.`\
\
`If this is your first time using Python, you should definitely check out`\
`the tutorial on the Internet at ``http://docs.python.org/tutorial/``.`\
\
`Enter the name of any module, keyword, or topic to get help on writing`\
`Python programs and using Python modules. To quit this help utility and`\
`return to the interpreter, just type "quit".`\
\
`To get a list of available modules, keywords, or topics, type "modules",`\
`"keywords", or "topics". Each module also comes with a one-line summary`\
`of what it does; to list the modules whose summaries contain a given word`\
`such as "spam", type "modules spam".`

Notice also that the prompt will change from \"`>>>`\" (three right
angle brackets) to \"help\>\" You can access the different portions of
help simply by typing in `modules`, `keywords`, or `topics`.

Typing in the name of one of these will print the help page associated
with the item in question. To get a list of available modules, keywords,
or topics, type \"modules\",\"keywords\", or \"topics\". Each module
also comes with a one-line summary of what it does; to list the modules
whose summaries contain a given word such as \"spam\", type \"modules
spam\".

You can exit the help system by typing \"quit\" or by entering a blank
line to return to the interpreter.

## Help Parameter

You can obtain information on a specific command without entering
interactive help.

For example, you can obtain help on a given topic simply by adding a
string in quotes, such as `help("object")`. You may also obtain help on
a given object as well, by passing it as a parameter to the help
function.

## External links

-   help in 2.
    Built-in Functions, docs.python.org

