Comparison of programming languages (functional programming)

This page provides the comparison tables of functional programming instructions between programming languages. Comparison of basic instructions of imperative paradigm is provided by the comparison of basic instructions.

List operations

Function applications and lists

For brevity, these words will have the specified meanings in the following tables (unless noted to be part of language syntax):

funcN

A function. May be unary or n-ary (or always unary for languages without n-ary functions).

func1, func2, etc.

functions of specific arity. func (with no number) is the same as func1, also known as a projection in many languages.

pred

Unary function returning a Boolean value. (ML type: 'a -> bool) (C-like type: bool pred<T>(T t)).

list

The list being operated on.

args

Comma-separated list of one or more argument names, in the form of arg1, arg2, ..., argn.

pattern

A pattern, in languages with pattern matching.

val

Any relevant value, depending on context.

	identity lambda	lambda	map	apply	filter	fold	sum
Python	lambda x: x	lambda args: expr	map(func, list)	nfunc(*arguments)	filter(pred, list)	functools.reduce(func2, list)	sum(list)
Mathematica	#&	(expr)& (arguments are #1, #2, etc.) Function[{args},expr]	Map[func, list] func /@ list	Apply[nfunc, args] nfunc@@args	Select[list, pred]	Fold[func2, val, list]	Apply[Plus,list] Plus@@list
C#	x => x	(args) => expr	Enumerable.Select(list, func)	Requires reflection	Enumerable.Where(list, pred)	Enumerable.Aggregate(list, func2) Enumerable.Aggregate(list, val, func2)	Enumerable.Sum(list) Enumerable.Sum(list, func)
Visual Basic .NET	Function(x) x	Function(args) expr
F# (can use Enumerable as well)	id(built-in) fun x -> x	fun pattern -> expr	Seq.map func list		Seq.filter pred list	Seq.fold func2 val list	Seq.sum list Seq.sumBy func list

Numerical operations on lists

comp

a binary function that returns a value indicating sort order (an integer in most languages).

	sort	max	min
Python	sorted(list)	max(list)	min(list)
Mathematica	Sort[list]	Max[list]	Min[list]
C#	Enumerable.OrderBy(list, comp)	Enumerable.Max(list, func)	Enumerable.Min(list, func)
Visual Basic .NET
F#	Seq.sort list Seq.sortBy comp list	seq.max seq.maxBy func list	seq.min seq.minBy func list

Iterations on lists

	group by
Python	itertools.groupby(list, func)
Mathematica	GroupBy[list, func]
C#	Enumerable.GroupBy(list, func)
Visual Basic .NET
F#	seq.groupBy func list

Generating lists by combinatorics tools

start

first value of range.

step

increment of range.

count

number of items in range.

last

inclusive last value of range.

end

exclusive last value of range.

	Generate range (lazily)	Infinite range (lazily)
Python	xrange(start, end, step) (Python 2) range(start, end, step) (Python 3)	itertools.count(start, step)
C#	Enumerable.Range(start, count)	Enumerable.Range(start, Int32.MaxValue)
Visual Basic .NET
F#	seq { start..step..last }	Seq.initInfinite func