Tuple Examples

Tuple Examples#

Note

Source: Python-specific — no direct equivalent in the C# edition. Examples draw on standard Python idioms for representing fixed-structure data such as coordinates, colours, and paired sequences.

Tuples as Records#

A tuple is a natural way to group a fixed number of related values when you do not need a full class:

# 2-D point
origin = (0, 0)
point = (3.0, -1.5)

# RGB colour
red = (255, 0, 0)
teal = (0, 128, 128)

# (name, grade) record
student = ("Alice", 91)

name, grade = student
print(f"{name} earned a {grade}")

Output:

Alice earned a 91

Tuples as Dictionary Keys#

Because tuples are immutable they can serve as dictionary keys — lists cannot:

# Map grid coordinates to a label
grid = {
    (0, 0): "origin",
    (1, 0): "east",
    (0, 1): "north",
}

print(grid[(1, 0)])

Output:

east

This is useful for representing two-dimensional data, graph edges, or any pairing that should be looked up quickly.

Iterating Paired Data with zip()#

zip() pairs elements from multiple sequences into tuples, making it easy to iterate over related data:

xs = [0, 1, 2, 3]
ys = [0, 1, 4, 9]

for x, y in zip(xs, ys):
    print(f"({x}, {y})")

Output:

(0, 0)
(1, 1)
(2, 4)
(3, 9)

Building a List of Tuples#

A common pattern is building a list of tuples to represent tabular data:

import math

table = [(n, n**2, math.sqrt(n)) for n in range(1, 6)]
for n, sq, root in table:
    print(f"{n:2d}  {sq:4d}  {root:.4f}")

Output:

1     1  1.0000
2     4  1.4142
3     9  1.7321
4    16  2.0000
5    25  2.2361

Sorting a List of Tuples#

sorted() compares tuples lexicographically by default (first element first, then second, etc.):

students = [("Carol", 85), ("Alice", 91), ("Bob", 78)]
by_name = sorted(students)
by_grade = sorted(students, key=lambda s: s[1], reverse=True)

print(by_name)
print(by_grade)

Output:

[('Alice', 91), ('Bob', 78), ('Carol', 85)]
[('Alice', 91), ('Carol', 85), ('Bob', 78)]