Python in a Nutshell

Name

__cmp__

Synopsis

__cmp__(self,other)

Any comparison, when its specific special method (__lt__, __gt__, etc.) is absent or returns NotImplemented, calls x .__cmp__( y ) instead, as do built-in function cmp( x,y ) and the sort method of list objects. __cmp__ should return -1 if x is less than y, 0 if x is equal to y, or 1 if x is greater than y. When __cmp__ is also absent, order comparisons (<, <=, >, >=) raise exceptions. Equality comparisons (= =, !=), in this case, become identity checks: x == y evaluates id( x )==id( y ) (i.e., x is y).