[Python-Dev] listcomps vs. for loops
Guido van Rossum
guido at python.org
Wed Oct 22 13:47:42 EDT 2003
> How about an until keyword in generator expressions:
New keywords are not on the table for generator expressions. You
could do this with 'while' (which is just 'until not' -- note that
your example uses that :-) but I'd be against making this part of the
syntax more complex. You can do that with itertools.takewhile or
> And we could have accumulators first() and last():
> def first(it):
> return it.next()
This begs for using a plain old loop statement with a 'break'.
> def last(it):
> for value in it:
> return value
What if it is empty?
> first(line for line in file if line.startswith("#"))
> if not last(file):
> # last line not terminated
The comment is incorrect.
--Guido van Rossum (home page: http://www.python.org/~guido/)
More information about the Python-Dev