Python match-case: Cleaner Alternative to if-elif Chains

Problem

Handling API responses often leads to long if-elif chains.

def handle_response(response):
    if response['status'] == 200:
        return process_data(response['data'])
    elif response['status'] == 404:
        return None
    elif response['status'] == 401 or response['status'] == 403:
        raise AuthError()
    elif response['status'] >= 500:
        raise ServerError()
    else:
        raise UnknownError(response['status'])

Add a few more conditions and it becomes hard to read.

Solution

Python 3.10+’s match-case makes this much cleaner.

def handle_response(response):
    match response:
        case {'status': 200, 'data': data}:
            return process_data(data)
        case {'status': 404}:
            return None
        case {'status': 401 | 403}:
            raise AuthError()
        case {'status': status} if status >= 500:
            raise ServerError()
        case _:
            raise UnknownError(response['status'])

The key feature is automatic destructuring. 'data': data extracts and binds the value in one step.

It works with class instances too:

from dataclasses import dataclass

@dataclass
class Point:
    x: float
    y: float

def describe(point):
    match point:
        case Point(x=0, y=0):
            return "origin"
        case Point(x=0, y=y):
            return f"on Y-axis ({y})"
        case Point(x=x, y=0):
            return f"on X-axis ({x})"
        case Point(x=x, y=y) if x == y:
            return f"on diagonal ({x})"
        case _:
            return f"general ({point.x}, {point.y})"

Key Points

• match-case is structural pattern matching, not just value comparison
• Use | to combine multiple patterns into one case
• Guard clauses with if allow additional filtering
• _ is the wildcard pattern, matching anything (works like else)
• Requires Python 3.10+