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Python program to get all subsets of given size of a set
• Difficulty Level : Easy
• Last Updated : 05 Feb, 2019

Given a set, write a Python program to generate all possible subset of size n of given set within a list.

Examples:

```Input : {1, 2, 3}, n = 2
Output : [{1, 2}, {1, 3}, {2, 3}]

Input : {1, 2, 3, 4}, n = 3
Output : [{1, 2, 3}, {1, 2, 4}, {1, 3, 4}, {2, 3, 4}]
```

We have already discussed the same problem using Naive approach in this article. This article focuses on the Pythonic approaches to Print all subsets of given size of a set.

Python has `itertools.combinations(iterable, n)` which Return n length subsequences of elements from the input iterable. This can be used to Print all subsets of given size of a set. Now, we have various alternatives to use this function.

Code #1 :
Simply pass the set as iterable and the size as arguments in the `itertools.combinations()` to directly fetch the combination list.

 `# Python Program to Print ``# all subsets of given size of a set`` ` `import` `itertools`` ` `def` `findsubsets(s, n):``    ``return` `list``(itertools.combinations(s, n))`` ` `# Driver Code``s ``=` `{``1``, ``2``, ``3``}``n ``=` `2`` ` `print``(findsubsets(s, n))`
Output:
```[(1, 2), (1, 3), (2, 3)]
```

Code #2 :
We can also use an alternative to above discussed method which is mapping set to `itertools.combinations()` function.

 `# Python Program to Print ``# all subsets of given size of a set`` ` `import` `itertools``from` `itertools ``import` `combinations, chain`` ` `def` `findsubsets(s, n):``    ``return` `list``(``map``(``set``, itertools.combinations(s, n)))``     ` `# Driver Code``s ``=` `{``1``, ``2``, ``3``}``n ``=` `2`` ` `print``(findsubsets(s, n))`
Output:
```[{1, 2}, {1, 3}, {2, 3}]
```

Code #3 :
Another method is to use for loop in `itertools.combinations()` function and append the combination sets to the list.

 `# Python Program to Print ``# all subsets of given size of a set`` ` `import` `itertools``# def findsubsets(s, n):``def` `findsubsets(s, n):``    ``return` `[``set``(i) ``for` `i ``in` `itertools.combinations(s, n)]``     ` `# Driver Code``s ``=` `{``1``, ``2``, ``3``, ``4``}``n ``=` `3`` ` `print``(findsubsets(s, n))`
Output:
```[{1, 2, 3}, {1, 2, 4}, {1, 3, 4}, {2, 3, 4}]
```

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