I tried overriding __and__, but that is for the & operator, not and - the one that I want. Can I override and?
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4 Answers
No you can't override and and or. With the behavior that these have in Python (i.e. short-circuiting) they are more like control flow tools than operators and overriding them would be more like overriding if than + or -.
You can influence the truth value of your objects (i.e. whether they evaluate as true or false) by overriding __nonzero__ (or __bool__ in Python 3).
2 Comments
DRayX
The control flow (lazy evaluation of the right hand side) semantics could still be maintained by having the overload be a binary operator where right hand side is passed as a callable instead of as a value.
kdb
@DRayX Not even that is necessary. The short-circuit part could simply be preserved as part of the operator, and the hypothetical
__and2__ function would only be called, if the first argument evaluates to a truthy value. a and b would be equivalent to a.__and2__(b) if a else a then. Not as regular as other operator functions, but that choice would enforce retaining short circuiting and provide better performance.You cannot override the and, or, and not boolean operators.
answered Jan 23, 2009 at 1:42
Ignacio Vazquez-Abrams
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Not really. There's no special method name for the short-circuit logic operators.
Comments
Although you can't overload __and__ you can use infix to overload and. You would use &and& to represent the and operator in this case.
1 Comment
Veky
No, you can not. (Since
and is a keyword in Python.)