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User-Defined Functions
User-defined functions are created by the user according to the needs of the program. Once the
user defines a function, the user can call it in the same way as the built-in functions. The main
difference between these two categories is that built-in functions do not require to be written
by us, whereas a user-defined functions are created by the programmer to address specific
requirements or perform custom tasks within a program.
CREATING A FUNCTION
We can create a function in the following ways:
Defining a Function: We use the def keyword to begin the function definition.
Naming a Function: Provide a meaningful name to your function.
Parameters: The parameters (separated by commas) are specified within the parenthesis
following the name of the function. These are basically the input values we pass to the
function.
Body of the Function: The body of the function contains Python statements that make our
function perform the required task.
The syntax of creating a function is as follows:
def < name of the function > (list of parameters)
<body>
CALLING A FUNCTION
A function can be called anytime from other functions or from the command prompt after
the definition. For calling a function, we type the function name and pass the parameters.
For example: To call a function
def my_function(): Name of a function
print (“Hello”) Body of a function
my_function() Function call
User-defined functions are divided into various categories based on their parameters and return
type. The functions that do not take any parameters and do not return any values are called type
1 functions.
The type 2 functions take parameters but do not return anything. The type 3 functions take
parameters and return values. Let us understand this with the help of an example:
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