When iterating over a list and removing each item, why is every other item skipped and not removed? (I realise it may be bad practice to do this I just want to understand what is going on)
lst=[0,1,2,3,4,5,6,7,8,9]
for item in lst:
lst.remove(item)
print(lst)
Expected output: []
Actual output: [1, 3, 5, 7, 9]
What happens here is the following:
You start with the following list:
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Then, in the first iteration of the for loop, you get the first item of the list which is 0, and remove it from the list. The updated list now looks like:
[1, 2, 3, 4, 5, 6, 7, 8, 9]
Then, at the second iteration of the loop, you get the second item in the updated list. Here, that second item is not 1 anymore but it is 2 (because you look at the updated list), so you remove 2 from the list. The updated list now looks like:
[1, 3, 4, 5, 6, 7, 8, 9]
And it goes on... until you get:
[1, 3, 5, 7, 9]