如何删除文件中每行的最后3个字符？

Question

Can anyone give me some advice on creating a loop to cut the last 3 characters from every line within a input file?

I have tried

iFile = iFile[:-3]

and

iFile = iFile.replace(':', '')[:-3]

but neither seem to work as I'm getting a:

TypeError: 'file' object has no attribute '__getitem__'

Answer 1

First open the file and then you will have to loop over the lines as follows

myfile = open(fileName)
for j in myfile:
    print j[:-3]

That all!

Answer 2

Replace

iFile = iFile[:-3]

with

line = line[:-3]

Answer 3

You can also use regular expression string substitution. This helps to prevent IndexError if you have lines that are shorter than three characters:

import re
with open(fileName, 'r') as myfile:
    for line in myfile:
        print re.sub('.{0,3}\Z', '', line)