Effect of '*' operation on list and list append in python

Question

code 1 and code 2 produce different outputs (even though same number 2 is being added to the list through + and append() operation )

Code 1:-

a=[ [ ] ]*4
a[0]=a[0]+[2]
a[0].append(2)
print(a).

Output1 - [ [2,2], [ ], [ ], [ ] ]
_________
Code 2
a=[ [ ] ]*4
a[0].append(2)
a[0]=a[0]+[2]
print(a)

Output 2 - [ [2,2], [2], [2], [2] ]

Can anyone throw a light on this difference?

Answer 1

Order matters ;)

Answer 2

Order matters that's right, but what surprised me is that in code 2 , a[0].append(2) puts 2 in all lists instead of only the first one