# RandomSample

RandomSample[{e1,e2,},n]

gives a pseudorandom sample of n of the ei.

RandomSample[{w1,w2,}{e1,e2,},n]

gives a pseudorandom sample of n of the ei chosen using weights wi.

RandomSample[{e1,e2,}]

gives a pseudorandom permutation of the ei.

# Details • RandomSample[{e1,e2,},n] never samples any of the more than once.
• RandomSample[{e1,e2,},n] samples each of the with equal probability.
• RandomSample[{e1,e2,},UpTo[n]] gives a sample of n of the ei, or as many as are available.
• RandomSample[i;;j;;k,n] may be used to sample the Span from i to j in steps of k.
• RandomSample gives a different sequence of pseudorandom choices whenever you run the Wolfram Language. You can start with a particular seed using SeedRandom.
• A Method option to SeedRandom can be given to specify the pseudorandom generator used.

# Examples

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## Basic Examples(3)

Find a sample in which no elements ever occur more than once:

Generate a random permutation:

Generate a random sample of 6 elements, or as many as there are if fewer:

## Scope(4)

The elements can be any expressions:

With larger weights for later elements, later elements tend to be selected for the sample:

Sample over all numbers between -10 and 10:

Sample over even numbers between -10 and 10:

Guarantee that a set of random integers over a big range has no repetitions:

## Applications(1)

Successively fill in black squares down the page:

## Properties & Relations(3)

Use SeedRandom to get repeatable random values:

Use BlockRandom to block one use of RandomSample from affecting others:

RandomSample of size 1 follows the same distribution as RandomChoice:

## Possible Issues(1)

If the sample size is larger than the population size, an error message is returned: Introduced in 2007
(6.0)
|
Updated in 2014
(10.0)
2015
(10.3)