*args

Overview

*args captures any number of positional arguments into a tuple. It enables functions to accept variable numbers of inputs — used extensively in decorator patterns, math utilities, and flexible APIs.

Syntax

python

def add_all(*args: int) -> int:
    return sum(args)

add_all(1, 2, 3)         # 6
add_all(10, 20, 30, 40)  # 100

# args is a tuple inside the function
def show(*args):
    print(type(args))    # <class 'tuple'>
    for item in args:
        print(item)

# Spreading a list with *
nums = [1, 2, 3]
add_all(*nums)   # same as add_all(1, 2, 3)

Common Pitfalls

*args must come after regular positional parameters and before **kwargs in the function signature.
The name 'args' is a convention — *anything works, but *args is universally understood.
Interview tip: *args in a function call (not definition) is the 'spread' or 'unpack' operator — it expands an iterable into positional arguments.

Real-World Example

A logging function that accepts variable message parts

example

python

import datetime

def log(*parts: str, level: str = "INFO") -> None:
    timestamp = datetime.datetime.now().strftime("%H:%M:%S")
    message = " ".join(str(p) for p in parts)
    print(f"[{timestamp}] [{level}] {message}")

log("Server started on port", 8080)
log("User", "alice@example.com", "logged in", level="DEBUG")
log("Critical failure", "DB unreachable", level="ERROR")

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