How to del item of a list in loop?
Reinhold Birkenfeld
reinhold-birkenfeld-nospam at wolke7.net
Sat Jan 15 02:38:34 EST 2005
skull 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:
> lst.remove(i)
>
> the result is:
>
> 1
> 2
>>>>
>
> 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.
Quick solution:
for i in lst[:]
iterates over a copy.
Reinhold
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