Tuples

A tuple looks like a list but with parentheses instead of square brackets, and behaves almost identically — except for one crucial difference: once created, a tuple can't be changed.

point = (3, 4)
print(point)
print(point[0])
x, y = point
print(x, y)

(3, 4)
3
3 4

That last line — x, y = point — is called unpacking, and it's one of the most useful things about tuples: pulling multiple values out into separate variables in one line.

Why immutability matters

Trying to modify a tuple after creating it doesn't quietly fail — it raises a real error. This is genuinely the output you'd get running this:

point = (3, 4)
point[0] = 10

Traceback (most recent call last):
  File "script.py", line 2, in <module>
    point[0] = 10
TypeError: 'tuple' object does not support item assignment

That's usually exactly what you want when a value genuinely shouldn't change after it's created — coordinates, RGB colors, a function returning multiple fixed values. If you need to add, remove, or change items later, use a list instead.

Next: dictionaries — storing values by name instead of by position.