Edit text file to add row numbers

[Boeileh]

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.tx t')
outfile = open('outfile.t xt','w')
for i in range(len(infil e)):
infile[i] = str(i) + ' ' + cb[i]
infile.close()
outfile.close()

Am I close :) ? Thanks for helping!

[Boeileh]

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

file = open("infile.tx t")
intext = file.read()
file.close()

for i in range(len(intex t)):
outtext[i] = str(i) + ' ' + intext[i]

file = open("outfile.t xt","w")
file.write(outt ext)
file.close()

[freddukes]

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

-freddukes

[Boeileh]

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

-freddukes

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

infile=open('infile.txt', 'r')
lines=infile.readlines()
infile.close()
inlist=list(lines)
outtext = {}
for i in range(len(inlist)):
    outtext[i] = str(i) + ' ' + inlist[i]
outfile = open("outfile.txt","w")
outfile.writelines(str(outtext))
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!

[bvdet]

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.

output = ['%d %s' % (i, line) for i, line in enumerate(f)]

Hint: Use the string method join() to write the modified data to disk.

[Boeileh]

It works! Thanks everybody!

This is the final code:

infile=open('2_2000.txt', 'r')
lines=infile.readlines()
infile.close()
outtext = ['%d %s' % (i, line) for i, line in enumerate(lines)]
outfile = open("3_2000.txt","w")
outfile.writelines(str("".join(outtext)))
outfile.close()

[bvdet]

It works! Thanks everybody!

This is the final code:

infile=open('2_2000.txt', 'r')
lines=infile.readlines()
infile.close()
outtext = ['%d %s' % (i, line) for i, line in enumerate(lines)]
outfile = open("3_2000.txt","w")
outfile.writelines(str("".join(outtext)))
outfile.close()

You can eliminate str() in the next to last line. Since join() returns one string, you can use f.write() or eliminate join().[code=Python]outfile.write(" ".join(outtext) )[/code]OR[code=Python]outfile.writeli nes(outtext)[/code]