Edit text file to add row numbers

Hi guys!
I just arrived here on this forum, and I hope you people can help me a bit with Python.

What I want is to edit a few large text files, by adding in front of each row the concerning rownumber. What I find out myself (not much..) is:

infile = open('infile.txt')
outfile = open('outfile.txt','w')
for i in range(len(infile)):
infile[i] = str(i) + ' ' + cb[i]
infile.close()
outfile.close()

Am I close :) ? Thanks for helping!

I now have this, but it is still not working..

file = open("infile.txt")
intext = file.read()
file.close()

for i in range(len(intext)):
outtext[i] = str(i) + ' ' + intext[i]

file = open("outfile.txt","w")
file.write(outtext)
file.close()

Hmmm... look into <open file>.readlines() and similarly <open file>.writelines()

-freddukes

Their is still something going wrong. This is the code I have now:

Expand|Select|Wrap|Line Numbers

1. infile=open('infile.txt', 'r')
2. lines=infile.readlines()
3. infile.close()
4. inlist=list(lines)
5. outtext = {}
6. for i in range(len(inlist)):
7.     outtext[i] = str(i) + ' ' + inlist[i]
8. outfile = open("outfile.txt","w")
9. outfile.writelines(str(outtext))
10. outfile.close()

If this is the input:
a
b
c

I want to have this:
0 a
1 b
2 c

What I receive with the code above is:
{0: '0 a\n', 1: '1 b\n', 2: '2 c\n'}

Who can give me the sollution? Thanks!

Given f, an open file object or list of lines from a file returned by file method readlines(), this one-liner will create a list of lines suitable for output to a file. Hint: Use the string method join() to write the modified data to disk.

It works! Thanks everybody!

This is the final code:

You can eliminate str() in the next to last line. Since join() returns one string, you can use f.write() or eliminate join(). OR