Variable examples in python

Python Variables with examples

Variables are used to store data, they take memory space based on the type of value we assigning to them. Creating variables in Python is simple, you just have write the variable name on the left side of = and the value on the right side, as shown below. You do not have to explicitly mention the type of the variable, python infer the type based on the value we are assigning.

num = 100 #num is of type int str = "Chaitanya" #str is of type string

Variable name – Identifiers

Variable name is known as identifier. There are few rules that you have to follow while naming the variables in Python.
1. The name of the variable must always start with either a letter or an underscore (_). For example: _str, str, num, _num are all valid name for the variables.
2. The name of the variable cannot start with a number. For example: 9num is not a valid variable name.
3. The name of the variable cannot have special characters such as %, $, # etc, they can only have alphanumeric characters and underscore (A to Z, a to z, 0-9 or _ ).
4. Variable name is case sensitive in Python which means num and NUM are two different variables in python.

Python Variable Example

num = 100 str = "BeginnersBook" print(num) print(str)

Output:

Python multiple assignment

We can assign multiple variables in a single statement like this in Python.

x = y = z = 99 print(x) print(y) print(z)

Another example of multiple assignment

a, b, c = 5, 6, 7 print(a) print(b) print(c)

Output:

Plus and concatenation operation on the variables

x = 10 y = 20 print(x + y) p = "Hello" q = "World" print(p + " " + q)

Output:

However if you try to use the + operator with variable x and p then you will get the following error.

unsupported operand type(s) for +: 'int' and 'str'

Data Types

A data type defines the type of data, for example 123 is an integer data while “hello” is a String type of data. The data types in Python are divided in two categories:
1. Immutable data types – Values cannot be changed.
2. Mutable data types – Values can be changed

Immutable data types in Python are:
1. Numbers
2. String
3. Tuple

Mutable data types in Python are:
1. List
2. Dictionaries
3. Sets

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Python Variables

A variable is created the moment you first assign a value to it.

Example

Variables do not need to be declared with any particular type, and can even change type after they have been set.

Example

Casting

If you want to specify the data type of a variable, this can be done with casting.

Example

Get the Type

You can get the data type of a variable with the type() function.

Example

Single or Double Quotes?

String variables can be declared either by using single or double quotes:

Example

Case-Sensitive

Variable names are case-sensitive.

Example

This will create two variables:

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