---Variables and data type in Python ---

 Variables: 

Variables can be considered as the name of a container. In other words, a variable is a container whose value can change depending on certain conditions. 

When we allocate a value to a variable, it is known as a variable assignment.

 In python, the syntax for it is variable_name = value

 Let's understand Variables with the help of a birthday card.

My birthday

1 st July 5:00 PM 

12/2, Rajouri Gardens 

9898463123

Now depending on whose birthday it is and who is being invited, the details being filled in the ‘_______’ (blank space) keep on changing…right? 

Imagine this ‘________’ as a container and the details being filled are the values. This value can change depending on circumstances.

Variables can be considered as the name of a container. So in the above example, 

date=”1 st July”

 address=”12/2, Rajouri Gardens”

 If the card is filled by someone else it can be, 

date=”21 st July”

 address=”34, MG road”

 Here, date, address, etc are containers (variables), and “1 st July”, ”12/2, ``Rajouri Gardens”, “21 st July” etc are values. 

Rules for forming Python variables: 

● A variable name must start with a letter or the underscore character.
● A variable name cannot start with a number. 
● A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )(space is not allowed)
● Variable names are case-sensitive (age, Age, and AGE are three different variables)

Datatype: 

Datatype is the type of value assigned to a variable. Depending on values that are assigned to a variable, a few common data types (variable type) in python are

suppose you want to take a printout of a birthday card. What details do you have to enter into the
computer, each time you take a printout? all the variables(like name, address, etc) have to be entered. And once you enter the variables, you will get the birthday card printed …right? So the variable data you enter is known as the input and the birthday card you get is the output. 

Output in python print () ->prints message given between () with newline(default) 

                                                                                                                                                                    Note : 

● “” is used with strings/ messages 
● If we give “” for the variable it will be considered as a string. 
● By default terminating the character of the print, the statement is a newline. 

Input in python

 ● input() 

 ● When the input() function executes program flow will be stopped until the user has given input. 

 ● By default, all input in python is taken as a string.

Syntax Input(). 
● returns the value entered by the user for the <message>  printed on-screen. 

●<message>  is optional.

program to get the name of the birthday boy from the user.

Now modify the above program to print his name on screen

In both the above versions, the name is the variable that holds the child’s name as a value.

Program to Get all the relevant details from users and prepare a birthday invitation card.

Program to Get all the relevant details as input and make a birthday invitation card Get the invitee address details from the user and print out an address slip to be pasted on the invitation card.

Output: