Why does a[0] change?

Question

When I do:

a = [7,3,4]
b = a
b[0] = 10

b[0] is of course set to 10, but a[0] is also set to 10. Why is this?

Useful related reading: http://stackoverflow.com/questions/17246693/what-exactly-is-the-difference-between-shallow-copy-deepcopy-and-normal-assignm — NightShadeQueen, Aug 28 '15 at 01:29

score 4 · Accepted Answer · answered Aug 28 '15 at 01:30

4

b = a

This makes b and a reference to the same list object. If you want b to reference to a new list object that is a copy of a, try:

b = a[:]

answered Aug 28 '15 at 01:30

Yu Hao

1 Answers1