Tuples & Sets

Tuples — ordered, immutable sequences.

coords = (10, 20)
point = (3.14, 2.71, 1.41)

coords[0]   # 10
x, y = coords  # unpacking

Use tuples for data that shouldn't change: coordinates, RGB values, database records.

Sets — unordered collections of unique values.

colors = {"red", "green", "blue"}
colors.add("yellow")
colors.remove("red")
"green" in colors   # True

Set operations:

a = {1, 2, 3, 4}
b = {3, 4, 5, 6}

a | b   # union: {1,2,3,4,5,6}
a & b   # intersection: {3,4}
a - b   # difference: {1,2}
a ^ b   # symmetric diff: {1,2,5,6}

When to use sets: Removing duplicates from a list (list(set(my_list))), membership testing (sets are O(1) vs list O(n)).

Reference:

Wikipedia: Set

https://en.wikipedia.org/wiki/Set_(abstract_data_type)