match.md

Python by Example: Match

Structural pattern matching (Python 3.10+) lets you match values against patterns—not just equality. It replaces long if/elif chains with clearer, more expressive code. You can match literals, sequences, dictionaries, and more. The _ pattern matches anything (like a default case).

What you'll learn:

• match and case syntax
• Matching literals, sequences, and dicts
• The wildcard _ for "anything else"

def describe(value):
    match value:
        case 0:
            return "zero"
        case 1 | 2:
            return "one or two"
        case [x, y]:
            return f"a pair: {x}, {y}"
        case {"name": n}:
            return f"dict with name: {n}"
        case _:
            return "something else"

print(describe(0))
print(describe(1))
print(describe([10, 20]))
print(describe({"name": "Alice"}))
print(describe(99))

case 1 | 2 matches either 1 or 2. case [x, y] matches a two-element list and binds the elements. case {"name": n} matches a dict with a "name" key. case _ catches everything else.

To run this program:

$ python source/match.py
zero
one or two
a pair: 10, 20
dict with name: Alice
something else

Tip: Match requires Python 3.10 or later. Check with python --version.

Try it: Add a new case for a three-element list [a, b, c].

Source: match.py

Next: Break and Continue