Python learning series | Day-5 Types of arguments

What is arguments?

Arguments are the values passed inside the parenthesis of the function. A function can have any number of arguments separated by a comma(,).

Types of arguments in python

1. Positional Arguments
2. Keyword Arguments
3. Default Arguments
4. Arbitrary / Variable-Length Arguments

1) Positional Arguments

These are the arguments to be passed in exact order in which the parameter are defined.

def greet(name,age):
    print(f"hello {name},Are you {age} year old")

greet("Ajay",20)

2) Keyword Arguments

We can pass arguments with explicitly stating the parameter name followed with value(name = value), the order of arguments doesn't matters.
-The keyword name must match the parameter name

def greet(name,age):
    print(f"hello {name},Are you {age} year old")

greet(age =20 ,name = "Ajay")

3) Default Arguments

You can assign fallback values to parameters in the function definition(declaration). If the caller skips providing a value for that argument, the predefined default value is used.

• Default arugments must always be placed after the non-default arugments in the function definition.

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

greet("harry")           
greet("harry", "Goodbye")

4) Arbitrary / Variable-Length Arguments

When you do not know beforehand how many arguments a user might pass, you use variable-length arguments:
• *args (Arbitrary Positional Arguments): Prefixed with a single asterisk, it collects extra positional arguments into a tuple.
• **kwargs (Arbitrary Keyword Arguments): Prefixed with a double asterisk, it collects extra keyword arguments into a dictionary.

def dynamic_function(*args, **kwargs):
    print("Positional tuple:", args)
    print("Keyword dictionary:", kwargs)

dynamic_function(1, 2, 3, status="active", role="admin")
# Output:
# Positional tuple: (1, 2, 3)
# Keyword dictionary: {'status': 'active', 'role': 'admin'}

4) Special boundries : Positional-Only, Keywords- Only

(/) and (*)strictly enforce how the arguments are suppied to the function

• Positional-Only(/) ---> Arguments before (/) must be passed as positional arguments not a keyword arguments.

def add(a,b,/,c):
    print(a+b+c)
add(20,30,c=20)   #valid
add(a=20,30,c=30)  #invalid

• Keyword-Only(*) ---> Arguments before (*) must be passed as keyword arguments not a positional arguments.

def add(a,b,*,c):
    print(a+b+c)
add(a=20,30,c=30)  #invalid
add(20,30,c=20)   #invalid