About the implementation of del in Python 3

[Terry Reedy]

On 7/6/2017 3:08 AM, Dan Wissme wrote:
> I thought that del L[i] would slide L[i+1:] one place to the left, 
> filling the hole, but :
> 
>  >>> L
> [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
>  >>> id(L)
> 4321967496
>  >>> id(L[5])    # address of 50 ?
> 4297625504
>  >>> del L[2]
>  >>> id(L[4])     # new address of 50 ?
> 4297625504
>  >>> id(L)
> 4321967496

> So the element 50 is still at the same memory location.
> What del L[i] do exactly, and what is its complexity ? O(1) or O(n) ?

A list is an array of references to objects that exist outside of the 
list.  Del deleted a reference, not any of the objects.

-- 
Terry Jan Reedy