Variable is a name which is used to refer memory location. Variable also known as identifier and used to hold value.
In Python, we don't need to specify the type of variable because Python is a type infer language and smart enough to get variable type.
Variable names can be a group of both letters and digits, but they have to begin with a letter or an underscore.
It is recomended to use lowercase letters for variable name. Rahul and rahul both are two different variables.
Variables are the example of identifiers. An Identifier is used to identify the literals used in the program. The rules to name an identifier are given below.
The first character of the variable must be an alphabet or underscore ( _ ).
All the characters except the first character may be an alphabet of lower-case(a-z), upper-case (A-Z), underscore or digit (0-9).
Identifier name must not contain any white-space, or special character (!, @, #, %, ^, &, *).
Identifier name must not be similar to any keyword defined in the language.
Identifier names are case sensitive for example my name, and MyName is not the same.
Examples of valid identifiers : a123, _n, n_9, etc.
Examples of invalid identifiers: 1a, n%4, n 9, etc.
Declaring Variable and Assigning Values
Python does not bound us to declare variable before using in the application. It allows us to create variable at required time.
We don't need to declare explicitly variable in Python. When we assign any value to the variable that variable is declared automatically.
The equal (=) operator is used to assign value to a variable.
Assigning Values to Variable
Python allows us to assign a value to multiple variables in a single statement which is also known as multiple assignment.
We can apply multiple assignments in two ways either by assigning a single value to multiple variables or assigning multiple values to multiple variables. Lets see given examples.
1. Assigning single value to multiple variables