Note: Function vs Module vs Library:

• A group of lines with some name is called a function
• A group of functions saved to a file , is called Module
• A group of Modules is nothing but Library Types of Variables Python supports 2 types of variables.
• Global Variables
• Local Variables
• Global Variables The variables which are declared outside of function are called global variables. These variables can be accessed in all functions of that module. Eg:

1) a=10 # global variable
2) def f1():
3) print(a)

4)

5) def f2():
6) print(a)

7)

Function 1

Function 2

Function 3

Module 1

Function 1

Function 2

Function 3

Module 2

Library

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• Function
• Local Variables: The variables which are declared inside a function are called local variables. Local variables are available only for the function in which we declared it.i.e from outside of function we cannot access. Eg:

1) def f1():
2) a=10
3) print(a) # valid

4)

5) def f2():
6) print(a) #invalid

7)

8) f1()
9) f2()

10)

11) NameError: name 'a' is not defined

global keyword:

We can use global keyword for the following 2 purposes:

• To declare global variable inside function
• To make global variable available to the function so that we can perform required modifications Eg 1:

1) a=10
2) def f1():
3) a=777
4) print(a)

5)

6) def f2():
7) print(a)

8)