Python Operations Comparisons - ashish9342/FreeCodeCamp GitHub Wiki
There are eight comparison operations in Python. They all have the same priority (which is higher than that of the Boolean operations). 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).
This table summarizes the comparison operations:
Operation | Meaning |
---|---|
< |
strictly less than |
<= |
less than or equal |
> |
strictly greater than |
>= |
greater than or equal |
== |
equal |
!= |
not equal |
is |
object identity |
is not |
negated object identity |
Objects of different types, except different numeric types, never compare equal. Furthermore, some types (for example, function objects) support only a degenerate notion of comparison where any two objects of that type are unequal. The <
, <=
, >
and >=
operators will raise a TypeError
exception when comparing a complex number with another built-in numeric type, when the objects are of different types that cannot be compared, or in other cases where there is no defined ordering.
Non-identical instances of a class normally compare as non-equal unless the class defines the __eq__()
method.
Instances of a class cannot be ordered with respect to other instances of the same class, or other types of object, unless the class defines enough of the methods __lt__()
, __le__()
, __gt__()
, and __ge__()
(in general, __lt__()
and __eq__()
are sufficient, if you want the conventional meanings of the comparison operators).
The behavior of the is and is not operators cannot be customized; also they can be applied to any two objects and never raise an exception.
TODO
- Chained comparisons w < x < y > z
- Equality comparison
is
vs==