How to del item of a list in loop?
bokr at oz.net
Sun Jan 16 01:38:01 EST 2005
On Sat, 15 Jan 2005 15:27:08 -0500, skull <skullw at sina.com.cn> wrote:
>Hi everybody, it is my first post in this newsgroup.
>I am a newbie for python though I have several years development experience in c++.
>recently, I was stumped when I tried to del item of a list when iteration.
>here is the wrong way I did:
>lst = [1, 2, 3]
>for i in lst:
> print i
> if i == 2:
>the result is:
>as you would see, '3' is missing. this problem is caused by 'lst.remove(i)'.
>apparently, 'marked-and-sweep' is a solution to deal with this issue.
>but I think there SHOULD BE more 'wise' trick. I want to get your help.
>Thanks in advance.
No one seems to have suggested this in-place way yet,
so I'll trot it out once again ;-)
>>> lst = [1, 2, 3]
>>> i = 0
>>> for item in lst:
... if item !=2:
... lst[i] = item
... i += 1
>>> del lst[i:]
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