Output of a code

Question

I can't understand why the output of this code

list = ["apple","banana","orange","mango"]
for item in list:
list.remove(item)
print(list)

is

>> ['banana', 'mango'] ???

I think all of the items in the list should be deleted.

Answer 1

https://code.sololearn.com/c75cb182xzAx/?ref=app
look at this Ebrahim Gholami

Answer 2

Ebrahim Gholami honestly idk

Answer 3

Ebrahim Gholami every other item in the list is removed.

Answer 4

It's because the "list" size was changing during iteration. This is what happened:
First, the for loop saw the first element in "list", i.e., list[0]="apple", and removed it from "list".

At the time, "list" became ["banana", "orange", "mango"] with length 3 but the for loop itself didn't notice this, and started the next iteration.

Then, for loop searched for list[1] and got "orange" and then remove it. The "list" became ["banana", "mango"] with length 2.

Finally, the for loop wanted to search for list[2] (the third element), but noticed that "list" has only length of 2 (no third element), so it stopped.

In fact, in this code, only elements of even number index (0,2,4...) will be removed.

If you want to remove all the elements, try this:

list=["apple", "banana", "orange", "mango"]
for item in list.copy():
list.remove(item)
print(list)

Answer 5

LONGTIE you're right but I want to know the reason of that .. I think for every item in the list the list.remove(item) should be applied.

Answer 6

thanks LONGTIE , I get it but how we can remove all of the items with a one "for loop"?

Answer 7

for some reason my playground doesnt work so I'll write here

list = ["apple","banana","orange","mango"]
for item in range(len(list)):
del list[0]
print(list)