Anand Chitipothu wrote:
On Wed, Jul 9, 2008 at 8:47 PM, Kushal Das <[EMAIL PROTECTED]> wrote:
Hi all,
a = [12, 12, 1321, 34, 23, 12, 34, 45, 77]
for x in a:
... if x == 12:
... a.remove(x)
a
[1321, 34, 23, 12, 34, 45, 77]
Can any one explain me how the remove works and how it is effecting the for
loop.
Others have explained why it fails. Here are two approaches for making it
work, in case you need ideas.
>>> a = [12, 12, 1321, 34, 23, 12, 34, 45, 77]
>>> filter(lambda x: x != 12, a)
[1321, 34, 23, 34, 45, 77]
The filter() build-in function is deprecated and the following is the
preferred way of doing it now:
>>> [x for x in a if x != 12]
[1321, 34, 23, 34, 45, 77]
Or if your list is quite large and you want to avoid making the new copy of
it, use the new list generator notation:
>>> b = (x for x in a if x != 12)
>>> for x in b:
... print x
1321
34
23
34
45
77
>>> list(b)
[1321, 34, 23, 34, 45, 77]
A list generator performs the filtering just-in-time as you need the elements.
-Jeff
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