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# Generate all permutation of a set in Python

• Difficulty Level : Easy
• Last Updated : 21 Jan, 2022

Permutation is an arrangement of objects in a specific order. Order of arrangement of object is very important. The number of permutations on a set of n elements is given by  n!.  For example, there are 2! = 2*1 = 2 permutations of {1, 2}, namely {1, 2} and {2, 1}, and 3! = 3*2*1 = 6 permutations of {1, 2, 3}, namely {1, 2, 3}, {1, 3, 2}, {2, 1, 3}, {2, 3, 1}, {3, 1, 2} and {3, 2, 1}.

Recommended Practice

Method 1 (Backtracking)
We can use the backtracking based recursive solution discussed here.
Method 2
The idea is to one by one extract all elements, place them at first position and recur for remaining list.

## Python3

 `# Python function to print permutations of a given list` `def` `permutation(lst):`   `    ``# If lst is empty then there are no permutations` `    ``if` `len``(lst) ``=``=` `0``:` `        ``return` `[]`   `    ``# If there is only one element in lst then, only` `    ``# one permutation is possible` `    ``if` `len``(lst) ``=``=` `1``:` `        ``return` `[lst]`   `    ``# Find the permutations for lst if there are` `    ``# more than 1 characters`   `    ``l ``=` `[] ``# empty list that will store current permutation`   `    ``# Iterate the input(lst) and calculate the permutation` `    ``for` `i ``in` `range``(``len``(lst)):` `       ``m ``=` `lst[i]`   `       ``# Extract lst[i] or m from the list.  remLst is` `       ``# remaining list` `       ``remLst ``=` `lst[:i] ``+` `lst[i``+``1``:]`   `       ``# Generating all permutations where m is first` `       ``# element` `       ``for` `p ``in` `permutation(remLst):` `           ``l.append([m] ``+` `p)` `    ``return` `l`     `# Driver program to test above function` `data ``=` `list``(``'123'``)` `for` `p ``in` `permutation(data):` `    ``print` `(p)`

Output:

```['1', '2', '3']
['1', '3', '2']
['2', '1', '3']
['2', '3', '1']
['3', '1', '2']
['3', '2', '1']```

Method 3 (Direct Function)
We can do it by simply using the built-in permutation function in itertools library. It is the shortest technique to find the permutation.

## Python3

 `from` `itertools ``import` `permutations` `l ``=` `list``(permutations(``range``(``1``, ``4``)))` `print``(l)`

Output:

`[(1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)] `

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