converting list back to string

Alex Martelli aleax at aleax.it
Tue Apr 22 23:47:10 CEST 2003


On Tuesday 22 April 2003 07:30 pm, regnivon at netscape.net wrote:
> Alex,
>
> Thank you for responding to my post.  I've included a copy of my original
> post because you said that it wasn't included on your feed.  Here it is:

Thanks!  Putting python-list back in, though...


> my code:
>
> import xreadlines
>
> input = open('c:/python22/programs/linetest.txt', 'r') # 3 lines of
> text
>
> output = open('c:/python22/programs/output.txt', 'w')
>
> for line in input.xreadlines():
>     remove = line.split()
>     remove[0:1] = []
>     output.write(remove)
>
> output.close()
> input.close()

If what you want is to remove the first field and let the rest of
each line unchanged, best might be (in Python 2.2 or better):

input = open('c:/python22/programs/linetest.txt', 'r')
output = open('c:/python22/programs/output.txt', 'w')

# loop directly on the file open for reading -- xreadlines is obsolescent
for line in input:
    # split selectively so most whitespace in the line's not disturbed
    first_field, rest_of_line = line.split(None, 1)
    output.write(rest_of_line)

output.close()
input.close()

i.e., this approach involves no lists at all.

> my quest:  i know that output.write(remove) is not correct.  you
> cannot use the 'write' method on a list.  is there a better way to

You could use output.writelines(remove), but that wouldn't give you
back your lost whitespace;-).

> this part of the program.  By the way, I have purchased the Python Cookbook
> and have been learning a lot about programming.  I appreciate you taking
> the time to help write the book and to answer my question.  I'm certainly a

Hope you're liking the Cookbook!  It may be aimed at programmers a bit
more experienced than you currenlty are, but I hope this just means you'll
be enjoying it for longer;-).

> newbie programmer, but Python seems to be the way to go. Scott

Absolutely -- there's no looking back from it!-).


Alex






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