Why is is-operator not functioning like ==?

Question

If I understand correctly, the is operator can take the place of ==.

Why when I write

if inpty == "exit":
    return

does the function exit, but when I write

if inpty is "exit":
    return

the function does not?

inpty is the value of the input.

Has been asked and explained here: http://stackoverflow.com/questions/1504717/python-vs-is-comparing-strings-is-fails-sometimes-why — sashkello, Apr 29 '13 at 00:51

score 3 · Accepted Answer · answered Apr 29 '13 at 00:52

3

is compares identity, whereas == compares equality.
In other words, a is b is the same as id(a) == id(b).

answered Apr 29 '13 at 00:52

icktoofay

score 1 · Answer 2 · edited Apr 29 '13 at 05:05

1

because in this case, the is operator is testing identity, not the value.

edited Apr 29 '13 at 05:05

Pradeep Pati

answered Apr 29 '13 at 00:51

Nomad101

the question was why does is not evaluate to true? and that is because it is testing identity not value? – Nomad101 Apr 29 '13 at 01:58

2 Answers2