Python Functions

  • date 17th July, 2019 |
  • by Prwatech |
  • 0 Comments

 

Python Functions Tutorial

 

Python Functions Tutorial, in this tutorial, we will learn Introduction to Function in Python and Type of Functions in Python. Here, You will also learn how to create and call a function in Python which is helpful for any Python developers. Are you looking for the Python functions tutorial with examples or Are you dreaming to become to certified Pro Python Developer, then stop just dreaming, get your Python certification course from India’s Leading Python training institute.

 

A function in any programming language is a set of statements in an order created by giving a name and when called a function, it will execute all statements. This is also known as Code reusability as no need to write code again and again for each data type in Python when we use Python functions. Do you want to know about how to create and call a function and types of functions in python, then just follow the below mentioned Python functions tutorial for Beginners from Prwatech and take advanced Python training like a Pro from today itself under 10+ years of hands-on experienced Professionals.

 

Introduction to Function in Python

 

A function is a block of code that only runs when it is called. You can pass inputs that are known as parameters, into a function. A function gives results by returning data or value. The function is created for the reusability of the same code.

 

Type of Functions in Python

 

We can find three kinds of functions in python:

 

Built-in Functions in Python

 

The First type is built-in functions, such as print() to print the expected value or result, min() to get the minimum value, bool()to get boolean value, etc.

 

User-Defined Functions in Python

 

The second type is User Defined Functions( UDF), which are functions created by users.

 

Anonymous functions in Python

 

The third type is ‘Anonymous functions’, which are also known as lambda functions. They are not declared with the standard keyword‘def’.

 

How to create a function in Python

 

We have to use ‘def’ to declare a function followed by a function’s name. Then we have to add parameters to the function within the parentheses of the function. The line should be ended with a colon. Statements to be executed are written on the next line. The function should be ended with the return statement if we expect some output. If we don’t write the return statement, the function will return ‘None’.

 

Ex) deftest():

print(“Python”)

return

 

Calling a Function

 

To call a function, we have to use the function name followed by round brackets (parenthesis):

Syntax:

function_name()

Above function can be called a test()

Output: Python

 

Python Function Arguments

 

Arguments are given to any function call, while the function mentions the arguments by their parameter names. There are four types of arguments for UDFs.

Default arguments

Required arguments

Keyword arguments

Variable number of arguments

 

Default argument

 

During the function call these arguments to take a default value if no argument is passed. We can allocate this default value with the assignment operator denoted by ‘=’.

Ex) def multi(x,y = 5):

return x * y

# Callingmulti() with only single parameter

multi(x=1)

Output:

5

# Call multi() with both x and y parameters

multi(x=1, y=3)

Output:

3

 

Required Arguments

 

During function call, these arguments need to be passed with the right order exactly, as shown in the following example:

Ex) def multi(x,y):

return x * y

# Calling function Output

multi(12,5)

Output:

60

 

Keyword Arguments

 

If we want to check whether all parameters are called sequentially or with the right order we use keyword argument. To identify the arguments by parameter names we use these keywords arguments.

Ex) # Defining function

def multi(x,y):

return x * y

# Calling function with parameters

multi(5,10)

Output:

50

# Calling the same function with keyword arguments

plus(x=5, y=10)

output:

50

 

Variable Number of Arguments:

 

If we don’t know the exact number of arguments to be passed while calling function, this provision is available in python. We can use * args in that case. Let’s see one example.

Ex)  # Defining function and try to give more than 2 arguments.

deftest(*args):

for in args:

print(i)

# Displaying the output

test(‘Variable’,’Number’,’type’,’ argument’)

Output:

The variable Number type argument

 

Anonymous Functions in Python

 

The anonymous function is called so, as this function has no name, which means it can’t be called with a particular name. This anonymous function is also known as ‘lambda function’, as it uses ‘lambda’ as a keyword instead of ‘def.’ It can take any number of arguments, but can only have one expression.

 

Syntax:

lambda arguments: expression

The expression is performed and the result is retained:

Ex) By using the single variable we can use a lambda function

x = lambda b : b + 30

print(x(5))

Output:

35

Ex)  Using more than one variable we can use lambda function as:

avg = lambda x,y :(x+y)/2

print(avg(5,7))

Output:

6.0

 

Why use Lambda Functions?

 

The benefit of lambda is, we can use it as an anonymous function inside another function. Suppose have a function definition that takes one argument, and that argument will be divided with an unknown number:

Ex) deffunc1(a):
return lambda b: b * a

 

We hope you understand Python functions tutorial with examples, python function arguments and Lambda Function in Python Programming concepts. Get success in your career as a Python developer by being a part of the Prwatech, India’s leading Python training institute in Bangalore.

 

 

 

 

 

 

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