Functions

Python Functions is a block of statements that return the specific task.

Example: A function that checks even and odd number.

def check(n):
    if n%2==0:
        return "Even"
    else:
        return "Odd"

print(check(5))

Types of Function Arguments

1. Keyword Argument

• No need to remember the order of argument.
• Use argument name and provide in any order.

>>> def fun(first, second):
...     return first+second
...
>>> fun(second="banana", first="apple")
'applebanana'

2. Default Argument

• A default argument is a parameter that assumes a default value if a value is not provided in the function call for that argument.

>>> def fun(a,b=5):
...     return a+b
...
>>> fun(4)
9

3. Variable Length Arguments

>>> def fun(*args, **kwargs):
...     for arg in args:
...             print(arg)
...     for key, value in kwargs.items():
...             print(f"{key} - {value}")
...
>>> fun(1,2,3, four=4, five=5)
1
2
3
four - 4
five - 5

4. Required Argument

• Required arguments are those that are required to be passed to the function at the time of function call.

>>> def fun(a, b):
...     return a+b
...
>>> fun(1,2)
3
>>> fun(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: fun() missing 1 required positional argument: 'b'

Lambda Function

A lambda function is typically used as a small, anonymous function.

square = lambda x: x**2
square(2)

numbers = [1, 2, 3, 4, 5]
squares = map(lambda x: x**2, numbers)
print(list(squares))  # Output: [1, 4, 9, 16, 25]