*args and **kwargs in Python

*args and **kwargs are used to allow functions to accept an arbitrary number of arguments. These features provide great flexibility when designing functions that need to handle a varying number of inputs.

The below code shows how *args collects multiple positional arguments into a tuple and how **kwargs collects keyword arguments into a dictionary.

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a 1
b 2
c 3

Symbols for Handling Variable Arguments

Python provides two special symbols for passing variable numbers of arguments:

• *args: Non-keyword (positional) arguments
• **kwargs: Keyword arguments

Note: Use *args or **kwargs when the number of arguments to be passed to a function is not known in advance.*

1. Non-Keyword Arguments (*args)

*args syntax allows a function to accept any number of positional arguments. All passed values are collected into a tuple, which can then be accessed or iterated inside the function. This is useful when the number of arguments is not known beforehand.

Hello
Welcome
to
GeeksforGeeks

Explanation:

• def myFun(*argv): defines a function that accepts any number of positional arguments.
• for arg in argv: loops through the tuple of arguments.

Here we use *args to multiply any number of values.

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Explanation:

• def multiply(*args): accepts multiple numbers as input.
• result = 1: initialize result to 1 (since we are multiplying).
• for num in args: loop through all arguments.
• result *= num: multiply each number with result.

2. Keyword Arguments (**kwargs)

**kwargs syntax allows a function to accept any number of keyword arguments. All arguments are collected into a dictionary, where the argument names become keys and their corresponding values become dictionary values.

s1 = Python
s2 = is
s3 = Awesome

Explanation:

• def fun(**kwargs): defines a function that accepts any number of keyword arguments.
• kwargs.items(): returns key-value pairs from the dictionary.

Here we use **kwargs to create a formatted string from the arguments.

Name: Alice, Age: 25, City: New York

Explanation:

• def introduce(**kwargs): accepts flexible keyword arguments.
• for k, v in kwargs.items(): loop through each key-value pair.
• details.append(k + ": " + str(v)): format each pair as key: value and add to list.
• ", ".join(details): join list items into a single string separated by commas.

Using both *args and **kwargs

We can also combine *args and **kwargs in the same function. This way, the function can accept both positional and keyword arguments at once.

Subjects: ('Math', 'Science', 'English')
Details: {'Name': 'Alice', 'Age': 20, 'City': 'New York'}

Explanation:

• *args: collects positional arguments into a tuple.
• **kwargs: collects keyword arguments into a dictionary.