I am getting back into python after a year of not doing it at all. I just wrote a bit of code to create a file that looks like this:1,21,1,1,1-1,0,142,17Then I decided to take the average of each line and put it into a list. For this I wrote the following:def line_averages():    out_file = open(data.csv, w) #create data file    out_file.write(1,2\n1,1,1,1\n-1,0,1\n42,17) #write numbers into data file    out_file.close()     f = open(data.csv, r) #read data file    lines = f.readlines()     avLines= [] #create a list to put averages into     for line in lines:        line2 = line.replace(\n, ) #remove /n from lines        line2 = line2.split(,) #split the lines by commas        Nlines = [] #create a list to put floats into        for i in line2:            i = float(i)            Nlines.append(i) #put the floats into the list        sums = sum(Nlines) #total up each line from the file        avLines.append(sums/len(line2)) #put the averages of each line into a list    return avLinesI'm pretty happy as this does exactly what I wanted but I can't help but wonder if it can't be shortened/simplified. It seems a bit inefficient to me to have lots of placeholders (like  Nlines or line2) which are used to do an operation rather than being able to do the operation directly on them. What would you guys do (if anything) to make this more compact? I'm sure it could be done more succinctly! 
Finding the average of each row in a CSV file
python;csv