On Mar 20, 11:00 am, Steven Bethard <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
> > for n,l in enumerate(open("file")):
> > print n,l # this prints current line
> > print next line in this current iteration of the loop.
>
> Depends what you want to happen when you request "next". If you want to
> renumber the lines, you can call .next() on the iterator::
>
> >>> open('temp.txt', 'w').write('1\n2\n3\n4\n5\n6\n7\n')
> >>> lines_iter = open('temp.txt')
> >>> for i, line in enumerate(lines_iter):
> ... print 'LINE %i, %r %r' % (i, line, lines_iter.next())
> ...
> LINE 0, '1\n' '2\n'
> LINE 1, '3\n' '4\n'
> LINE 2, '5\n' '6\n'
> Traceback (most recent call last):
> File "<interactive input>", line 2, in <module>
> StopIteration
>
> If you want to peek ahead without removing the line from the iterator,
> check out this recipe::
>
> http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/304373
>
> Which allows code like::
>
> >>> lines_iter = peekable(open('temp.txt'))
> >>> for i, line in enumerate(lines_iter):
> ... print 'LINE %i, %r %r' % (i, line, lines_iter.peek())
> ...
> LINE 0, '1\n' '2\n'
> LINE 1, '2\n' '3\n'
> LINE 2, '3\n' '4\n'
> LINE 3, '4\n' '5\n'
> LINE 4, '5\n' '6\n'
> LINE 5, '6\n' '7\n'
> Traceback (most recent call last):
> ...
> StopIteration
>
> (Note that the recipe doesn't try to catch the StopIteration, but if you
> want that suppressed, it should be a pretty simple change.)
>
> STeVe
thanks, lines_iter.next() is what i need at the moment.
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