Functions

Functions are a fundamental building block in Python programming, allowing you to organize code, promote reusability, and simplify complex tasks. It takes input arguments (optional) and returns a result (optional).

Using function

Functions are groups of code that have a name and can be called using parentheses.
print('abc').Here, print is the function name, and 'abc' is the function’s argu‐ ment.

Defining and Calling Functions

Function syntax: def function_name(parameters)

  def greet(name):
      print("Hello, " + name + "!")

  greet("Nirmal")  # Output: Hello, Nirmal!
  greet("Retrica")    # Output: Hello, Retrica!

Parameters and Return Values

Parameters are placeholders for values passed to a function.
Functions can have multiple parameters.

Return statement: specifies the value a function should return.

  def add(a, b):
      return a + b

  result = add(3, 5)
  print(result)  # Output: 8

Recursive Functions

A function can call itself, creating a recursive function.

Useful for solving problems that can be broken down into smaller instances.

  def factorial(n):
      if n == 0:
          return 1
      else:
          return n * factorial(n - 1)

  print(factorial(5))  # Output: 120

Anonymous(lambda) Functions

An anonymous function, also known as a lambda function, is a function in Python that is defined without a name.
It is a compact way of creating small, one-line functions without the need for a formal function definition.

Syntax is : lambda arguments: expression

  '''Formal Function'''
  def add(x,y):
      return x + y
  print(add(2,3))# output = 5

  '''Lambda Function - 1'''
  add = lambda x,y:x+y
  print(add(2,3)) # output = 5

  '''Lambda Function - 2'''
  print((lambda x,y:x+y)(2,3))# output = 5

*args and **kwargs

*args and **kwargs are useful when you do not know how many arguments will be passed to your function. They allow you to pass a variable number of arguments to a function.

*args

The *args syntax allows you to pass a variable number of non-keyword arguments to a function.

It collects arguments into a tuple.

  def add(*nums):
      total = 0
      for n in nums:
          total += n
      return total

  print(add(1, 2, 3))
  # output = 6

**kwargs

The **kwargs syntax allows you to pass a variable number of keyword arguments to a function.

It collects arguments into a dictionary.

  def userDetails(**user):
        for key,value in user.items():   
            print(f'{key} is a {value}')

  userDetails(name="Nirmal", age=23, country="Nepal")

  #Output:
  #name is a Nirmal
  #age is a 23
  #country is a Nepal

Using both args and kwargs

  def combineArgs(arg1, arg2, *args, **kwargs):
      print(arg1)
      print(arg2)
      print(args)
      print(kwargs)

  combineArgs(1, 2, 3,4,5, key1='a', key2='b')

Built-in Functions

Some built-in functions are : print(), len(), input(), range(), type(), int(), float(), str(), max(), min(), abs(), sum(), and round().

  import math
  print(math.sqrt(16))  # Output: 4.0

  # Example 2: len()
  my_list = [1, 2, 3, 4, 5]
  print(len(my_list))# Output: 5

  # Example 3: input()
  name = input("Enter your name: ")
  print("Hello,", name)

  # Example 4: range()
  for num in range(5):
      print(num)
  # Output: 0 1 2 3 4

  # Example 5: type()
  x = 10
  print(type(x))# Output: <class 'int'>

  # Example 6: int(), float(), str()
  num1 = "10"
  num2 = int(num1)
  print(num2)# Output: 10

  # Example 7: max(), min()
  my_list = [3, 7, 2, 9, 5]
  print(max(my_list))# Output: 9

  # Example 8: abs()
  x = -5
  print(abs(x))# Output: 5

  # Example 9: sum()
  my_list = [1, 2, 3, 4, 5]
  print(sum(my_list))# Output: 15

  # Example 10: round()
  x = 3.14159
  print(round(x, 2))# Output: 3.14

Functions

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Using function

Defining and Calling Functions

Parameters and Return Values

Recursive Functions

Anonymous(lambda) Functions

*args and **kwargs

Built-in Functions

Command Palette

Comments

Python Tutorials

Higher order and Partial Functions

More from this blog

Using function

Defining and Calling Functions

Parameters and Return Values

Recursive Functions

Anonymous(lambda) Functions

*args and **kwargs

Built-in Functions