Python Function Parameters and Arguments

Parameters are variables defined in a function declaration. This act as placeholders for the values (arguments) that will be passed to the function.

Arguments are the actual values that you pass to the function when you call it. These values replace the parameters defined in the function.

Although these terms are often used interchangeably, they have distinct roles within a function. This article focuses to clarify them and help us to use Parameters and Arguments effectively.

Parameters

A parameter is the variable defined within the parentheses when we declare a function. 

Example:

# Here a,b are the parameters
def sum(a,b):
  print(a+b)
  
sum(1,2)

3

Arguments

An argument is a value that is passed to a function when it is called. It might be a variable, value or object passed to a function or method as input.

Example:

def sum(a,b):
  print(a+b)
  
# Here the values 1,2 are arguments
sum(1,2)

3

Types of arguments in python

Python functions can contain two types of arguments:

• Positional Arguments
• Keyword Arguments

Positional Arguments

Positional Arguments are needed to be included in proper order i.e the first argument is always listed first when the function is called, second argument needs to be called second and so on.

Example:

def fun(s1,s2):
  print(s1+s2)
  
fun("Geeks","forGeeks")

GeeksforGeeks

Note: The order of arguments must match the order of parameters in the function definition.

Variable-Length Positional Arguments

To handle multiple arguments within the function, you can use *args.

def fun(*args):
    # Concatenate all arguments
    result = "".join(args)
    print(result)

# Function calls
fun("Geeks", "forGeeks")          # Two arguments

To read in detail, refer - *args and **kwargs in Python

Keyword Arguments

Keyword Arguments is an argument passed to a function or method which is preceded by a keyword and equal to sign (=). The order of keyword argument with respect to another keyword argument does not matter because the values are being explicitly assigned.

def fun(s1, s2):
    print(s1 + s2)


# Here we are explicitly assigning the values
fun(s1="Geeks", s2="forGeeks")

GeeksforGeeks