Random

A random element of a domain: uniform over a finite collection or an interval, or drawn from a distribution; with a count or shape, that many draws.

✓ checked against that system · ! checked, with disagreements (hover a chip)Wolfram LanguageRandomReal✓↗

Random()A real in $[0, 1)$.

Random(domain, shape)One draw from a finite collection, uniform by index, or an interval; with a count, that many draws, and with a list of dimensions, an array of that shape. Every draw comes from the engine's one seeded stream, restarted by SeedRandom.

Random(dist, shape)Draws from a distribution, by its own sampler.

Typed signatures

Type	Package	Applies
(() random -> real) & ((collection<any> | set<real>) random -> any) & ((collection<any> | set<real>, integer<0..> | list<integer<0..>>) random -> list)	combinatoricsreplaces compute-engine	always
(() random -> real) & ((collection<any> | set<real>) random -> any) & ((collection<any> | set<real>, integer<0..> | list<integer<0..>>) random -> list) & ((distribution, (integer<0..> | list<integer<0..>>)?) random -> any)	statisticsreplaces combinatorics	always
((collection<any> | set<real>)?) random -> any	compute-engine	always

Domain: Compute engine

Examples

Basic #

one permutation of $\{1, 2, 3, 4\}$, drawn uniformly by index from the collection; seeded, so it is the same every time

live ↗

In$\mathrm{Last}(\bigl\lbrack\mathrm{SeedRandom}(4), \mathrm{Random}(\mathrm{Permutations}(4))\bigr\rbrack)$Out${\operatorname{Permutation}}([4, 3, 1, 2])$

Scope #

a count after the domain draws that many elements

live ↗

In$\mathrm{Length}(\mathrm{Last}(\bigl\lbrack\mathrm{SeedRandom}(1), \mathrm{Random}(\mathrm{IntegerPartitions}(10), 3)\bigr\rbrack))$Out$3$

Properties & Relations #

RandomInteger is its Wolfram spelling over a Range: the same draw from the same stream

live ↗

In$\mathrm{Last}(\bigl\lbrack\mathrm{SeedRandom}(5), \mathrm{RandomInteger}(\bigl\lbrack10, 20\bigr\rbrack)\bigr\rbrack)=\mathrm{Last}(\bigl\lbrack\mathrm{SeedRandom}(5), \mathrm{Random}(10..20)\bigr\rbrack)$Out$\mathrm{True}$

About

Examples	3
Checked against	Wolfram Language 2 agreeCombinatorica 1 agree
Crosswalk	Wolfram Language

See also: SeedRandom, RandomInteger, RandomVariate