Multiple Function Parameters

Note

Source: Adapted from the C# edition (functions/funcparam2.rst). Keyword arguments and default-value parameters are Python-specific original additions.

A function can have more than one parameter. Parameters are listed in the def line separated by commas.

Example: Addition

def print_sum(a, b):
    total = a + b
    print(f"The sum of {a} and {b} is {total}.")

print_sum(3, 4)
print_sum(10, 25)

Output:

The sum of 3 and 4 is 7.
The sum of 10 and 25 is 35.

When you call print_sum(3, 4): - parameter a receives the value 3 - parameter b receives the value 4

This matching is positional — the first argument goes to the first parameter, the second to the second, and so on.

Keyword Arguments

You can also pass arguments by name (called keyword arguments):

>>> print_sum(b=4, a=3)
The sum of 3 and 4 is 7.

With keyword arguments, order does not matter. We will see keyword arguments used more heavily later (for example, print(end="") uses them).

Default Values

Parameters can have default values. If the caller omits the argument, the default is used:

def greet(name, greeting="Hello"):
    print(f"{greeting}, {name}!")

greet("Alice")            # uses default greeting
greet("Bob", "Hi there")  # overrides default

Output:

Hello, Alice!
Hi there, Bob!

Parameters with default values must come after parameters without defaults.