python iterate over a list, remove item, why result is not empty?

Asked Jul 29 '15 at 08:42

Active Jul 29 '15 at 08:42

Viewed 36 times

I tried this:

mylist = range(20)

for item in mylist:
    mylist.remove(item)

len(mylist) == 20

Why the result is not [] ?

asked Jul 29 '15 at 08:42

longnight

.remove returns a copy of the list. Use mylist = mylist.remove(item) – Stiffo Jul 29 '15 at 08:54
2

Repeat after me. Never, ever modify the list that you are iterating over, it causes all kinds of problems. Rather, iterate over the original list and modify a copy (using the index). – Bas Jansen Jul 29 '15 at 08:55
No , .remove() returns a None, and modified the list. @Stiffo – longnight Jul 29 '15 at 09:32

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