I create a python list and cannot get expected output, how to fix it?

Asked Apr 05 '22 at 03:16

Active Apr 05 '22 at 03:16

Viewed 23 times

code:

ans = [set()] * 3
ans[1].add('s')
print(ans)

output:

[{'s'}, {'s'}, {'s'}]

my expected output is [{},{'s'},{}]

code:

ans = [[]] * 3
ans[1].append('s')
print(ans)

output:

[['s'], ['s'], ['s']]

my expected output is [[],['s'],[]]

WHY??

asked Apr 05 '22 at 03:16

Dian He

1

`[set()] * 3` is creating a list with *three references to the same `set`*. Like if you had done`s = set()` then `ans = [s, s, s]` – juanpa.arrivillaga Apr 05 '22 at 03:22

0 Answers0