16. Sets
16.1. Sets
Unlike lists and tuples, sets hold an unordered collection of elements with no duplicates. This makes them suitable for testing membership or removing duplicate elements.
set = {8, 12, 22}
# Add a single element to set
set.add(42)
# Add several elements to set
set.update([16, 32, 64])
# Remove an element from set - throws an error if element not in set
set.remove(42)
# Remove an element if present in set
set.discard(42)
Since a set is an unordered collection of elements, indexing is not possible. Python supports typical set operation methods:
set_a = {1,2,3,4,5}
set_b = {4,5,6,7}
set_c = {1,2}
# Check for membership
2 in set_a
# Return elements in the intersection of set_a and set_b
set_a.intersection(set_b)
# Return true if set_a contains all the elements of set_c
set_a.issuperset(set_c)
An empty set is created using a set() method, as using braces creates an empty dictionary (see below).
For more methods, visit Python documentation.