2. USER DEFINED FUNCTIONS: A function defined by programmer/user
according to their need
Advantages of User-defined Functions in Python
• This Python Function help divide a program into modules. This makes the code
easier to manage, debug, and scale.
• It implements code reuse. Every time you need to execute a sequence of
statements, all you need to do is to call the function.
• This Python Function allow us to change functionality easily, and different
programmers can work on different functions.
The syntax to define a function is:
To define your own Python function, you use
the ‘def’ keyword before its name. And its name is to be followed by parentheses,
before a colon(:). Parenthesis may contain argument(s) i.e. parameter(s).
#Syntax of function without parameters
def functionname( ):
"function_docstring"
Statement1
.
.
#Syntax of function without parameters
def functionname( arg1,arg2,.... ):
"function_docstring"
Function statement
.
.
return (expression)
Example:
# A simple Python function to check
# whether x is even or odd
def evenOdd( x ):
if (x % 2 == 0):
print "even"
else:
print "odd"
# Driver code to call the function
evenOdd(2)
evenOdd(3)
Function Parameter(s):
A functions has two types of parameter(s):
1. Formal Parameter: Formal parameters are written in the function prototype
and function header of the definition. Formal parameters are local variables
which are assigned values from the arguments when the function is called.
