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Match Case Statement in Python

 


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Match-Case Statements

In Python 3.10 and later, the match-case statement was introduced as a way to perform pattern matching, similar to switch-case statements in other programming languages. It allows you to check the value of a variable against multiple patterns and execute corresponding blocks of code.

Basic Match-Case Statement

The match statement is followed by an expression and several case clauses. Each case specifies a pattern and an action to be taken if the pattern matches the value of the expression.


# Basic match-case statement example
command = "start"

match command:
    case "start":
        print("Starting...")
    case "stop":
        print("Stopping...")
    case "pause":
        print("Pausing...")
    case _:
        print("Unknown command")

Matching Multiple Patterns

Using the pipe symbol |, you can match multiple patterns in a single case clause.


# Matching multiple patterns example
status = "open"

match status:
    case "open" | "opened":
        print("The status is open.")
    case "closed" | "shut":
        print("The status is closed.")
    case _:
        print("Unknown status")

Using Guards in Case Clauses

Guards allow you to add additional conditions to a case clause using the if keyword.


# Using guards in case clauses example
number = 42

match number:
    case x if x >> 0:
        print("The number is positive")
    case x if x == 0:
        print("The number is zero")
    case x if x < 0:
        print("The number is negative")

Pattern Matching with Data Structures

The match-case statement can also be used to match patterns in data structures like lists and tuples.


# Pattern matching with lists example
data = [1, 2, 3]

match data:
    case [1, 2, 3]:
        print("Matched [1, 2, 3]")
    case [4, 5, 6]:
        print("Matched [4, 5, 6]")
    case _:
        print("No match")
    

# Pattern matching with tuples example
point = (4, 5)

match point:
    case (0, 0):
        print("The point is at the origin")
    case (x, y):
        print(f"The point is at ({x}, {y})")
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