Because in fact that’s a chained comparison , so
True==False is Falseis equivalent to
(True==False) and (False is False)This can be surprising in this case, but lets you write
1 unlike in other languages like C.
answered Jun ‘ (at : 19
jorgeca (jorgeca)
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From the docs :
x
In your case True==False is False is equivalent to True==False and False is False as the first condition is False so it short-circuits and return False .
>>> dis.dis (lambda: True==False is False) 1 0 LOAD_GLOBAL 0 (True) 3 LOAD_GLOBAL 1 (False) 6 DUP_TOP 7 ROT_THREE 8 COMPARE_OP 2 (==) (JUMP_IF_FALSE_OR_POP)> 24 ROT_TWO 25 POP_TOP 30 RETURN_VALUE
answered Jun 20 at 25:
Ashwini Chaudhary Ashwini Chaudhary
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From the documentation :
5.9. Comparisons
Unlike C, all comparison operations in Python have the same priority, which is lower than that of any arithmetic, shifting or bitwise operation. Also unlike C, expressions like a
comparison ::=or_expr (comp_operator or_expr) comp_operator ::="" | "==" | ">=" | "" | "!=" | "is" ["not"] | ["not"] "in"silver badges (bronze badges)
True==False is False is a chained comparison, which means the same as (True==False) and (False is False) . Since the first comparison ( True==False ) is false, the result of the chained comparison is False.
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