Why is list.remove only removing every second item?

Question

In my Python 2.7.2 IDLE interpreter:

>>> mylist = [1, 2, 3, 4, 5]
>>> for item in mylist:
        mylist.remove(item)

>>> mylist
[2,          


        

Answer 1

>>> mylist = [1, 2, 3, 4, 5]

>>> for item in mylist:
        mylist.remove(item)

in this loop : 1st time it will take 0th element (1) as an item and remove it from mylist.so after that mylist will be [2,3,4,5] but the pointer will be in the 1th element of the new mylist ([2,3,4,5]) that is 3. and it will remove 3.so 2 will not be remove from the list.

thats why after the full operation [2,4] will be left.

using for loop:-
>>>for i in range(len(mylist)):
       mylist.remove(mylist[0])
       i-=1

>>>mylist
[]

you can do this using while loop:

>>>mylist = [1, 2, 3, 4, 5]
>>>while (len(mylist)>0):
       mylist.remove(mylist[0])
       print mylist