Variables in Python

Variables

Variables are named container in memory that holds a value of a certain type. The value can be accessed in a program by calling the name of the varible that is defined.

Variables are like containers which can hold a value. Hence, they can be very useful when we need to store a value (such as number, string, boolean etc.) in a program.

Syntax of a variable in python

To use a variable in python, you can write something like this.

a = 1

Here we have name of a variable in left-hand side a (it can be anything) and on other side of equal to sign, we have a numerical value 1 assigned to a.

In similar fashion, we can define as many variables as we want to have in a program.

a = 1
b = 67

Accessing variables in program

We can use these values by typing the name of the variable. We will be printing them on terminal.

a = 12
b = 8
print(a)
print(b)

NOTE: To access a variable in print() you don't have to enclose it in quotes (like "a"). As if written in quotes, it would be a string that would print a as it is not 8 (it's value).

Use of variables

Variables can be used in such ways:

• Storing values that will be used later in program.

x = 1
y = 2
 
# using x and y for addition
print(a + b)

• Storing results of a calculation

cal = 2*2-3
print(cal) # output: 1

Data types in Python

Data type defines what type of value a variables can hold.

We have these common data types:

• Integers (int): Stores values like ...,-3,-2,-1,0,1,2,3,...
• Floating Point numbers (float or double): Stores values like 1.23, 0.42, 444.211 ,....
• Character (char): Stores values like 'a', 'b', 'c' ...
• Boolean (bool): Stores values like True or False
• String (str): Stores sequence of characters like "codeSarv", "You are great", etc.

However, python is a dynamically-typed language which means it automatically detects and accepts whichever type of value is being stored, at runtime.

So you can store any kind of value in a varaible.

a = 1 # int
b = 2.2 # float
c = 'a' # str
d = 'a rainy day' # str
e = True
 
print(type(a))
print(type(b))
print(type(c))
print(type(d))
print(type(e))

The type() function is a built-in function that returns type of the value passed in it.

To access the value you can alway do this.

# accessing values of a, b, c, d and e variables defined earlier
print("Value of a = ", a)
print("Value of b = ", b)
print("Value of c = ", c)
print("Value of d = ", d)
print("Value of e = ", e)

The content enclosed in quotes is string that would print as it is. Those which written without quotes are variables and their value would get printed. You can print multiple items in one print statement by separating them with commas ,.