transformed map(tranformationiteratorcomprehension transformed (transformation(xfor in iteratorclassic "fp-stylefiltered filter(predicateiteratorcomprehension filtered ( for in iterator if predicate( )the function functools reduce(is very generalvery powerfuland very subtle to use to its full power it takes successive items of an iterableand combines them in some way the most common use case for reduce(is probably covered by the built-in sum()which is more compact spelling offrom functools import reduce total reduce(operator addit total sum(itit may or may not be obvious that map(and filter(are also special cases of reduce(that isadd lambda nn+ reduce(lambda lxl+[add ( )]range( )[][ simplermap(add range( )isodd lambda nn% reduce(lambda lxl+[xif isodd(xelse lrange( )[][ simplerfilter(isoddrange( )these reduce(expressions are awkwardbut they also illustrate how powerful the function is in its generalityanything that can be computed from sequence of successive elements can (if awkwardlybe expressed as reduction there are few common higher-order functions that are not among the "batteries includedwith pythonbut that are very easy to create as utilities (and are included with many third-party collections of functional programming toolsdifferent libraries--and other programming languages--may use different names for the utility functions describebut analogous capabilities are widespread (as are the names choose higher-order functions