Generate all subsets of size k (containing k elements) in Python

by

Seems like you want itertools.combinations:

>>> list(itertools.combinations((1, 2, 3), 2))
[(1, 2), (1, 3), (2, 3)]

If you want sets you’ll have to convert them explicitly. If you don’t mind an iterable instead of a list, and you’re using Python 3, you can use map:

>>> s = set((1, 2, 3))
>>> map(set, itertools.combinations(s, 2))
<map object at 0x10cdc26d8>

To view all the results at once, you can pass the output of map to list. (In Python 2, the output of map is automatically a list.)

>>> list(map(set, itertools.combinations(s, 2)))
[{1, 2}, {1, 3}, {2, 3}]

However, if you know you’ll need a list, a list comprehension is marginally better (h/t Jacob Bowyer):

>>> [set(i) for i in itertools.combinations(s, 2)]
[{1, 2}, {1, 3}, {2, 3}]

More Related Contents:

  1. How to compare a list of lists/sets in python?
  2. Making a sequence of tuples unique by a specific element
  3. how to unpack a tuple in this form (‘abc’, [20, 20])? [closed]
  4. Why can’t I use a list as a dict key in python?
  5. Why can tuples contain mutable items?
  6. List vs tuple, when to use each? [duplicate]
  7. How to change values in a tuple?
  8. Python convert tuple to string
  9. Empty set literal?
  10. Accessing a value in a tuple that is in a list
  11. How to convert a list to a list of tuples?
  12. How does Python’s comma operator work during assignment?
  13. How to check if one dictionary is a subset of another larger dictionary?
  14. Tuple or list when using ‘in’ in an ‘if’ clause?
  15. Is python’s “set” stable?
  16. Sorting a tuple that contains tuples
  17. JSON serialize a dictionary with tuples as key
  18. Get unique values in List of Lists
  19. What is time complexity of a list to set conversion?
  20. Convert a columns of string to list in pandas
  21. Python Class __div__ issue
  22. Understanding the set() function
  23. How to create a “singleton” tuple with only one element
  24. How to convert a set to a list in python?
  25. Does Python have an immutable list?
  26. How to check if a tuple contains an element in Python?
  27. Swap values in a tuple/list inside a list in python?
  28. A set union find algorithm
  29. python – get list of tuples first index?
  30. In what case would I use a tuple as a dictionary key? [closed]

Leave a Comment