# Generate All Permutations of a List in Python

This tutorial discusses methods to generate all permutations of a list in Python.

## Use `itertools.permutations` to Generate All Permutations of a List in Python

Python provides a standard library tool to generate permutations: `itertools.permutation`. The below example shows how to use this to generate all permutations of a list.

``````import itertools
inp_list = [4, 5, 6]
permutations = list(itertools.permutations(inp_list))
print(permutations)
``````

Output:

``````[(4, 5, 6), (4, 6, 5), (5, 4, 6), (5, 6, 4), (6, 4, 5), (6, 5, 4)]
``````

The default length of the permutation is set to be the length of the input list. However, we can specify the length of the permutation in the `itertools.permutations` function call. The below example illustrates this.

``````import itertools
inp_list = [1, 2, 3]
permutations = list(itertools.permutations(inp_list, r=2))
print(permutations)
``````

Output:

``````[(4, 5), (4, 6), (5, 4), (5, 6), (6, 4), (6, 5)]
``````

The below example illustrates how to generate all permutations of all possible lengths of a given list.

``````import itertools
inp_list = [1, 2, 3]
permutations = []
for i in range(1,len(inp_list)+1):
permutations.extend(list(itertools.permutations(inp_list, r=i)))
print(permutations)
``````

Output:

``````[(4,), (5,), (6,), (4, 5), (4, 6), (5, 4), (5, 6), (6, 4), (6, 5), (4, 5, 6), (4, 6, 5), (5, 4, 6), (5, 6, 4), (6, 4, 5), (6, 5, 4)]
``````

## Use Recursion to Generate All Permutations of a List in Python

We can also use recursion to generate all permutations of a list in Python. The below example illustrates this.

``````def permutations(start, end=[]):
if len(start) == 0:
print(end)
else:
for i in range(len(start)):
permutations(start[:i] + start[i+1:], end + start[i:i+1])

permutations([4,5,6])
``````

Output:

``````[4, 5, 6]
[4, 6, 5]
[5, 4, 6]
[5, 6, 4]
[6, 4, 5]
[6, 5, 4]
``````
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