Can somebody explain the output of this code snippet

Question

Can anybody explain me the output of the below code ?

a=[ [7,8], 9, 9]

b=a[:]

a[2]= 200

a[0][1]=17

print (a)

print (b)

Output

[[7, 17], 9, 200]
[[7, 17], 9, 9]

Answer 1

By making a copy of a list through slicing which is b=a[:]

So any change in a will not affect to b unless there is no nested values inside a.

If so any changing in that nested value will affect to b too.

This is a demonstration of pass by "object" reference.