Python Variables | How to declare Python variables?

Before understanding Python Variables let’s first discuss what variables means?

What are variables?

Variables are used to store the values in programming languages. Values are like integer, decimal, Boolean, string etc. every language has its own way to create variables.  So we will discuss here variables in Python and how we can create Python variables and use it.

 

Python Variables:

If you want to know how to create Python variable, then it’s very easy. You have to just write the name of the variable and assign the value to it that’s it. You are done with python variable.

Name_of_the_variable= value_of_the_variable

Example: Let’s take example


age = 20

print (age)

here age is variable in python whose value is 20. When we run this program we will get 20

output

20

Unlike other language, Python variables are very easy to declare and use, as they don’t require any data type. E.g. in java if variable will hold integer value then it will have defined as int age, but in python its nothing like that. We have to simply write the variable name only, no data type required here. Which make python variables very easy to create and use.

Points to remember about Python variables:

  • Python Variables are case-sensitive. It means variable age is different and Age will be different variable.

age=20

Age=26

Here age and Age are two different variables.

  • Python variable can only be start with letter and underscore (_). Variable cannot be start with any special character other than underscore.

spoon=20  –  valid

_tree = 20 – valid

(glass = 20 – invalid

  • Python variable cannot be start with number, but number in-between is allowed.

1age = 20 –Invalid

Age123 = 20- valid

 

Examples of Python Variables

Let’s see some examples of python Variable

 

Store number value in variable


age=28

print(age)

 

output

28

 

Store decimal value in variable


price=125.50

print(price)

 

output

125.5

 

Store String value in variable


Name= "Python"

print(Name)

 

output


Python

 

Concatenation of variables: we can concatenate two or more variables.

For example


greeting="hi! "

Name= "Python"

print (greeting + Name)

 

output


hi! Python

 

Here we have concatenate two python variable greeting and Name

Important point: String to string variables, number to number, decimal to decimal, number to decimal variable we can concatenate directly, but for string and number numbers we have to type cast them

Example


greeting="hi!"

Name= "Python"

age=30

print (greeting + Name + str(age))

 

Output


hi!Python30

Here age is number and other two variables are String, so before concatenate the number, we have to type cast into String.

If we don’t typecast age to String, we will get following error:


TypeError: must be str, not int

 

Get type of Python variable

In Python, we can also get the type of the variable means what type of variable it is. Its whether number, or String etc.

There is a type() function in python, which determine the type of variable in python.

Syntax: type(variable_name)

 

Example: let’s take the same example, now we will find the data type of variables


greeting="hi!"

Name= "Python"

age=30

print (type(greeting))

print (type(age))

 

Output will be

<class ‘str’>
<class ‘int’>

 

Variable greeting is of type string and age variable is of type integer (number).

 

 

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