# Permutations

Permutations[list]

generates a list of all possible permutations of the elements in list.

Permutations[list,n]

gives all permutations containing at most n elements.

Permutations[list,{n}]

gives all permutations containing exactly n elements.

# Details # Examples

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## Basic Examples(2)

Length-3 permutations of {a,b,c}:

Length-3 permutations of {a,b,c,d}:

## Scope(4)

Repeated elements are treated as identical:

Use any expressions as elements:

Get permutations of all lengths, shortest ones first:

Get even-length permutations, longest ones first:

## Generalizations & Extensions(1)

The list of elements can have any head:

## Properties & Relations(4)

The number of length-n permutations of a length-n list of distinct elements is n!:

The number of length-r permutations of a length-n list of distinct elements is FactorialPower[n,r]:

A permutation that leaves no element invariant is called a derangement:

The number of derangements of n distinct elements is Subfactorial[n]:

If the input list is in the order given by Sort, so are its length-r permutations: