Lesson 1, Topic 1
In Progress

Functions Copy


A convenient way to divide the code into useful blocks is by using what we call as a function. A function can be understood as block of instructions that performs a single and related action. The use of functions in a code makes it more readable and saves the programmer’s time. Functions can be classified as built-in functions and user-defined functions. Built-in functions as the name suggests are already a part of the Python library. These are predefined in the Python programming interface. On the other hand, user-defined functions are the functions that are invoked or called by the user to be used in a code. These types of functions are not pre-existing and are defined as per the user’s imagination.

In Python, a function is defined using a special word (we call key word: def), followed by the name of the function and the place holders (arguments) for the values when we call this function.

Python has many built-in functions such as:
print( ) : Prints an object specified in the code as an output.
int( ) : Converts a string or a number datatype to an integer datatype.
len( ) : Returns the length of an object.

Syntax:    def functionname( parameters ):

def printas( str ):“This prints a passed string into this function”
# Now you can call printas function
printas(“My Name is XYZ”)
printas(“I love Python programming”)

This code will generate the following output:
My Name is XYZ
I love Python programming

Note that the function “print(str)” is a built-in function whereas “printas( )” is a user-defined function.