What is the difference between arguments and parameters in Python?

The concepts of arguments and parameters are fundamental parts of functions in Python. Understanding their difference is crucial for writing effective Python code.

A parameter is a variable listed inside the parentheses in the function definition. An argument is the actual value passed to the function when it is called.

Basic Function Example

Let's start with a simple function to understand the basics ?

# Define a function
def greet():
    print("Hello, World!")

# Function call
greet()

Hello, World!

Function with Parameters

Here's a function that accepts parameters ?

# Function with parameter 'car_name'
def display_car(car_name):
    print("Car =", car_name)

# Function calls with different arguments
display_car("Tesla")
display_car("BMW")
display_car("Toyota")

Car = Tesla
Car = BMW
Car = Toyota

Parameters vs Arguments

In the function definition, car_name is the parameter. When calling the function, "Tesla", "BMW", and "Toyota" are the arguments.

Multiple Parameters and Arguments

Functions can have multiple parameters and accept multiple arguments ?

# Function with multiple parameters
def employee_info(name, rank):
    print("Employee Name =", name)
    print("Employee Rank =", rank)
    print("-" * 20)

# Function calls with different arguments
employee_info("Alice", 1)
employee_info("Bob", 2)
employee_info(rank=3, name="Charlie")  # Keyword arguments

Employee Name = Alice
Employee Rank = 1
--------------------
Employee Name = Bob
Employee Rank = 2
--------------------
Employee Name = Charlie
Employee Rank = 3
--------------------

Key Differences

Advanced Example

Here's an example with different types of parameters ?

def calculate(x, y=10, *args, **kwargs):
    print(f"x (positional): {x}")
    print(f"y (default): {y}")
    print(f"args (variable positional): {args}")
    print(f"kwargs (variable keyword): {kwargs}")

# Function call
calculate(5, 15, 25, 35, name="Alice", age=30)

x (positional): 5
y (default): 15
args (variable positional): (25, 35)
kwargs (variable keyword): {'name': 'Alice', 'age': 30}

In this example, x, y, *args, and **kwargs are parameters. The values 5, 15, 25, 35, "Alice", and 30 are arguments.

Conclusion

Parameters are placeholders in function definitions, while arguments are the actual values passed during function calls. Understanding this distinction helps write clearer, more maintainable Python code.