Python Introduction | Lists, Tuples, Ranges, Sets, and Dictionaries | Working with Sets

Lists, tuples, and ranges are sequences. Their values have an order and can be accessed by index. A set is different: it stores unique values without an index-based order.

Create a set with braces or with set.

variable = {value1, value2, ...}
variable = set([value1, value2, ...])

Sets are useful for membership checks and set operations.

Set Operations

Adding a Value

set_value.add(value)

Adding an existing value does not change the set.

Removing a Value

set_value.remove(value)

Obtaining the Number of Elements

variable = len(set_value)

Obtaining Maximum and Minimum Values

variable = max(set_value)
variable = min(set_value)

Set Difference

set1 - set2

Returns a new set containing values from set1 that are not in set2.

Comparing Sets

Use ==, !=, <, <=, >, and >= to compare sets. The ordering operators represent subset and superset relationships, not numeric size. For example, A > B checks whether A is a proper superset of B.

Logical Set Operations

set1 & set2
set1 | set2
set1 ^ set2

a = {'a', 'b'}
b = {'b', 'c'}
c1 = a & b
c2 = a | b
c3 = a ^ b
print(c1)
print(c2)
print(c3)