Comparison of programming languages (functional programming)

List operations

Function applications and lists

For brevity, these words will be 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
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

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#[1] Enumerable.OrderBy(list, comp) Enumerable.Max(list, func) Enumerable.Min(list, func)
Visual Basic .NET[1]
F#[2] 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)[3]
Mathematica GroupBy[list, func][wolfram 1]
C#[1] Enumerable.GroupBy(list, func)
Visual Basic .NET[1]
F#[2] 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)[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]
F#[2] seq { start..step..last } Seq.initInfinite func

References

  1. "Enumerable Class (System.Linq)". Microsoft Docs. Microsoft. Retrieved 2019-08-29.
  2. "Collections.Seq Module (F#)". Microsoft Developer Network. Microsoft. Retrieved 2019-08-29.
  3. "itertools — Functions creating iterators for efficient looping". Python 3.7.4 documentation. Python Software Foundation. Retrieved 2019-08-29.
  4. "Built-in Functions". Python 2.7.16 documentation. Python Software Foundation. Retrieved 2019-08-29.
  5. "Built-in Types". Python 3.7.4 documentation. Python Software Foundation. Retrieved 2019-08-29.
  1. "GroupBy". Wolfram Language Documentation. Wolfram. Retrieved 2019-08-29.


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