Need solution

Question

a=[8,0,4,6,1]
del(a[1::3])
print(sum(a))

How the output is 18?

Answer 1

The slice a[1::3] gives [0,1], because it holds references to a[1] and a[4]. Using del(a[1::3]) has the same effect as removing the reference to the values 0 and 1 in the list, so what remains is [8, 4, 6], of which the sum is 18.