Intermediate Python for Scripting Function Parameters

Learning objective: By the end of this lesson, students will be able to utilize different types of function parameters in Python.

Function parameter types

Python supports different types of function parameters:

1. Required parameters

These are parameters that must be provided when calling the function. In the greet function, name is a required parameter.

2. Default parameters

We can assign default values to parameters, making them optional. If an argument is not provided for a default parameter, the function uses the default value. Here’s an example:

intermediate_python.py

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

In this modified version of the greet function, greeting is a default parameter with a default value of "Hello". We can call the function with or without providing a value for greeting:

intermediate_python.py

greet("Alice")
# Prints: Hello, Alice!
greet("Bob", "Hi")
# Prints: Hi, Bob!

3. Variable-length parameters

Python allows functions to accept a variable number of arguments using *args and **kwargs syntax. *args is used to pass a variable number of non-keyword arguments, while **kwargs is used to pass a variable number of keyword arguments. Here’s an example:

intermediate_python.py

def sum_numbers(*args):
    total = 0
    for num in args:
        total += num
    return total

In this example, the sum_numbers function accepts any number of arguments and returns their sum. We can call the function with multiple arguments:

intermediate_python.py

result = sum_numbers(1, 2, 3, 4, 5)
print(result)
# Prints: 15

Write a function called process_numbers that accepts any number of numerical arguments and sums their values.

Experiment with the function by adding your own tests or by modifying the operations performed.