are compounded equality tests short circuited in python?

Question

Does python short circuit a boolean like a==b==c, i.e., if a==b is false, then the second equality isn't evaluated? Is the compound equality just syntactic sugar for a==b and b==c?

Does this answer your question? [Does Python support short-circuiting?](https://stackoverflow.com/questions/2580136/does-python-support-short-circuiting) — Numilani, Dec 12 '19 at 20:41
@Ambrosia only if the answer to my second question about syntactic sugar is "yes" — Hasse1987, Dec 12 '19 at 20:42

score 5 · Accepted Answer · edited Dec 12 '19 at 22:25

5

Yup. From the docs:

Comparisons can be chained arbitrarily, e.g., x < y <= z is equivalent to x < y and y <= z, except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false).

This applies to any chained comparison, regardless of the chosen comparison operators.

edited Dec 12 '19 at 22:25

Arn

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answered Dec 12 '19 at 20:43

user2357112

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score 3 · Answer 2 · answered Dec 12 '19 at 20:44

3

From the Python docs:

Comparisons can be chained arbitrarily; for example, x < y <= z is equivalent to x < y and y <= z, except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false).

answered Dec 12 '19 at 20:44

Numilani

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are compounded equality tests short circuited in python?

2 Answers2