Can someone explain to me why in Python 15 is 15 but -15 is not -15? Does that make any sense?
In [1]: -15 is -15
Out[1]: False
In [2]: 15 is 15
Out[2]: True
It looks like -15 is an instance of something.
Asked
Active
Viewed 32 times
0
Cecile
- 1,553
- 1
- 15
- 26
-
1A small integer cache is the gist of it, also in play (at other instances), peep-hole optimizer. In short, these are implementation details that shouldn't really concern you. – Dimitris Fasarakis Hilliard Jun 08 '17 at 10:09
-
is is the identity equality operator (functioning like id(a) == id(b)); it's just that two equal numbers aren't necessarily the same object. Instead of using "is" try to check with "==" ;) – Marco smdm Jun 08 '17 at 10:13
-
Thanks, makes sense now https://docs.python.org/2/c-api/int.html @Marcosmdm you're not helping ;) – Cecile Jun 08 '17 at 10:13
-
Exactly, the C-API does mention this :-) – Dimitris Fasarakis Hilliard Jun 08 '17 at 10:14
-
The funny thing is that "foo" is "foo"... it's totally counter intuitive. – Cecile Jun 08 '17 at 10:16