Advanced Functions:
===================
Q: Why the data/function declaration is not mandatory in Python?
=================================================================
Ans: Because the Python dynamically typed/Instant Typed programming language

x = 123	# integer
x = 1.23 # float
x = "Python" # String

Syntax for function definition:
===============================
Note: 
====
Function declaration is not required in Python

def function-name(parameters with comma separation):
	statement-1
	statement-2
	statement-3
	return value

=====================================================
Types of Variables
==================
==> Three types of variables:
	1) Local Variables
	2) Global Variables
	3) Non-Local Variables

1) Local Variables
==================
==> always define within the function body and we can access within the same function.
==> the scope of the local variables is function scope.

# Local Variables

def localVariables():
    a = 100
    b = 200

    print("Local Variables are:")
    print("a = ",a)
    print("b = ",b)

localVariables()
# print("Local Variables are:")
# print("a = ",a)
# print("b = ",b)

===========================================
def LocalVariables(a,b,c):
    # the function parameters are also act as local variables
    print("The Local Variables are:")
    print("a = ",a)
    print("b = ",b)
    print("c = ",c)

LocalVariables(10,20,30)
# print("a = ",a)
# print("b = ",b)
# print("c = ",c)
=========================================
a = -10
b = 20

if a > 5 and b != 0:
    c = 30
    print("a = ",a)
    print("b = ",b)
    print("c = ",c)
else:
    print("a = ", a)
    print("b = ", b)
    # print("c = ", c)
==============================================

2) Global Variables
===================
==> can always define in outside the function.
==> Global scope ==> we can access the global variable in anywhere of the program
Ex: program ==> 3-functions
a variable have defined in outside of all 3 functions
==> that variable we can access in fun1, fun2 and fun3 also.

a = 100
b = 200
c = 300

def function1():
    # pass
    print("The Given Global Variables are:")
    print("a = ",a)
    print("b = ",b)
    print("c = ",c)

# pass ==> keyword in python
# to define an empty block or empty function or empty class, we can use pass in the implementation section.
# to make execute the function without implementation as normal function,
# we can use "pass" statement.

def function2():
    # pass
    # when local variables and global variables with same name, function can
    # prioritize to local variables first.
    # print("The Given Global Variables are:")
    # print("a = ", a)
    # print("b = ", b)
    # print("c = ", c)

    # global keyword can help to define the global variables within the function
    # also can be used to modify the global variables
    # using the global keyword we should only declare the variable but we can't assign/initialize the value.
    global a
    global b
    global c

    a = 111
    b = 222
    c = 333

    print("The Given Global Variables after the modification are:")
    print("a = ", a)
    print("b = ", b)
    print("c = ", c)

def function3():
    # pass
    print("The Given Global Variables are:")
    print("a = ", a)
    print("b = ", b)
    print("c = ", c)

function1()
function2()
function3()

print("The Given Global Variables are:")
print("a = ",a)
print("b = ",b)
print("c = ",c)
==================================================
3) Non-Local Variables
======================
keyword ==> nonlocal
==> a variables are not defined in either local or global scope are called as "non-local variables".
==> use in nested functions
==> function in function ==> nested function

def outerFunction():
    a = 15
    b = 30  # a and b ==> local variables for outerFunction but these are global variables
    # in innerFunction
    print("a = ", a)    # 15
    print("b = ", b)    # 30
    def innerFunction():
        nonlocal a
        nonlocal b
        a = 10
        b = 20
        print("a = ",a)
        print("b = ",b)
        return a+b
    print(innerFunction())
    print("a = ",a)
    print("b = ",b)

outerFunction()
# print("a = ",a)
# print("b = ",b)

Function Aliasing
==================
List ==> List Aliasing
Set ==> Aliasing

==> function aliasing means assigning alterative name to the function.

def greetings(name):
    print("Hi",name)
    print("Good Evening")

greetings("Ravi")

wishes = greetings  # function aliasing
wishes("Keerthi")

greetings("Karthik")