Dr Mephesto wrote:
> Hi,
> Im new to python, and OOP, and am trying to get a handle on list
> comprehension.
>
> Say I have a class Foo with a property called bar:
>
> class Foo:
> def __init__(self):
> self.bar = random.randint(1,100)
>
> and then I make a list of these objects:
>
> Newlist = []
> for x in range(10):
> Newlist.append(Foo())
>
> Now, suppose I wanted to triple the value of 'bar', I could always do:
>
> for x in range(10):
> Newlist[x].bar = Newlist[x].bar * 3
>
> but can I do this using list comprehension? Thanks in Advance!
No, as such, because list-comprehensions require you to have an *expression*
in front of the iteration:
resultlist = [<expr> for <variable(s)> in <iterable>]
Now what you of course can do is this:
def multiply(item):
item.bar = item.bar * 3
[multiply(i) for i in items]
However, doing this will make python produce a list of None-references -
which is a waste. It's up to you if you care about that, but generally it
is frowned upon because of that, and the fact that the conciseness of the
list-comp here isn't really helping with the readability.
Diez
--
http://mail.python.org/mailman/listinfo/python-list
