skip last line in loops

[Fredrik Lundh]

eight02645999 at yahoo.com wrote:

>> do it lazily:
>>
>>      last_line = None
>>      for line in open("file):
>>          if last_line:
>>              print last_line
>>          last_line = line
>>
>> or just gobble up the entire file, and slice off the last item:
>>
>>      for line in list(open("file"))[:-1]:
>>          print line
>>
>> </F>
 >
> would it be a problem with these methods if the file is like 20Gb in
> size...?

not with the lazy version, of course.   the "gobble up" version will 
load the entire file into memory.

but cutting off a single line from a 20 gigabyte file by looping over
it sounds like a bit contrived, really.  if you're really doing this 
(why?), maybe you should just truncate the file in place instead.

</F>