Hi -- I have many sections of code like this:
for value in value_iterator:
value_function(value)
I noticed that this does two things I don't like:
1. looks up "value_function" and "value" for each iteration, but
"value_function" doesn't change.
2. side effect of (maybe) leaking the iterator variable "value" into
the code following the loop (if the iterator is not empty).
I can take care of 2 by explicitly deleting the variable at the end:
del value
but I'd probably forget to do that sometimes. I then realized that,
in the 2.x series, I can accomplish the same thing with:
map(value_function, value_iterator)
and avoid both problems BUT map() returns a list which is never used.
Not a big deal for small iterables, I guess, but it seems messy. Upon
conversion to 3.x I have to explicitly list-ify it:
list(map(value_function, value_iterator))
which works but again the list returned is never used (extra work) and
has to be gc'd I suppose (extra memory).
It's easy to make a little function to take care of this (2.x):
from itertools import imap
def apply(function, iterable):
for item in imap(function, iterable):
pass
then later:
apply(value_function, value_iterator)
or something similar thing in 3.x, but that just adds an additional
function def that I have to include whenever I want to do something
like this.
So.....I'm wondering if there is any interest in an apply() built-in
function that would work like map() does in 2.x (calls the function
with each value returned by the iterator) but return nothing. Maybe
"apply" isn't the best name; it's just the first one that occurred to
me.
Or is this just silly and should I forget about it?
--
Gerald Britton
--
http://mail.python.org/mailman/listinfo/python-list
