Why output come like this

Question

A=[1,2,3,4]
B=A
A[0]=0
B[1]=9
print(B)
print(A)

Output >> [0, 9, 3, 4]
[0, 9, 3, 4]

Why not [1, 9, 3, 4]
[0, 2, 3, 4]

Answer 1

About the topic references, see here for more details:

https://code.sololearn.com/c89ejW97QsTN/?ref=app

Answer 2

I doesn't change second element of A, and first element of B, But in output both are changed🤔

Answer 3

to copy a list
B=A[:]