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

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#^[1]	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^[1]	Function(`x`) `x`	Function(`args`) `expr`	Enumerable.Select(`list`, func)		Enumerable.Where(`list`, pred)		Enumerable.Sum(`list`) Enumerable.Sum(`list`, func)
F#^[2] (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`

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#^[1]	Enumerable.OrderBy(`list`, comp)	Enumerable.Max(`list`, func)	Enumerable.Min(`list`, func)
Visual Basic .NET^[1]	Enumerable.OrderBy(`list`, comp)	Enumerable.Max(`list`, func)	Enumerable.Min(`list`, func)
F#^[2]	Seq.sort `list` Seq.sortBy comp `list`	seq.max seq.maxBy func `list`	seq.min seq.minBy func `list`

	group by
Python	itertools.groupby(`list`, func)^[3]
Mathematica	GroupBy[`list`, func]^{[wolfram 1]}
C#^[1]	Enumerable.GroupBy(`list`, func)
Visual Basic .NET^[1]	Enumerable.GroupBy(`list`, func)
F#^[2]	seq.groupBy func `list`

	Generate range (lazily)	Infinite range (lazily)
Python	xrange(start, end, step) (Python 2)^[4] range(start, end, step) (Python 3)^[5]	itertools.count(start, step)
C#^[1]	Enumerable.Range(start, count)	Enumerable.Range(start, Int32.MaxValue)
Visual Basic .NET^[1]	Enumerable.Range(start, count)	Enumerable.Range(start, Int32.MaxValue)
F#^[2]	seq { start..step..last }	Seq.initInfinite func

^ ^a ^b ^c ^d ^e ^f ^g ^h "Enumerable Class (System.Linq)". Microsoft Docs. Microsoft. Retrieved 2019-08-29.
^ ^a ^b ^c ^d "Collections.Seq Module (F#)". Microsoft Developer Network. Microsoft. Retrieved 2019-08-29.
^ "itertools — Functions creating iterators for efficient looping". Python 3.7.4 documentation. Python Software Foundation. Retrieved 2019-08-29.
^ "Built-in Functions". Python 2.7.16 documentation. Python Software Foundation. Retrieved 2019-08-29.
^ "Built-in Types". Python 3.7.4 documentation. Python Software Foundation. Retrieved 2019-08-29.

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