Python Variables

Variables

Variables are containers for storing data values.

Creating Variables

Python has no command for declaring a variable.

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

Example

 
x = 5

y = "John"

print(x)

print(y)

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

Example

 
x = 4       # x is of type int

x = "Sally" # x is now of type str

print(x)

Casting

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

Example

 
x = 
  str(3)    # x will be '3'
y = int(3)    # y 
  will be 3
z = float(3)  # z will be 3.0

Get the Type

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

Example

 
x = 5
y = "John"
print(type(x))
print(type(y))

Single or Double Quotes?

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

Example

 
x = "John"
# is the same as
x = 
  'John'

Case-Sensitive

Variable names are case-sensitive.

Example

This will create two variables:

 
a = 4
A = 
  "Sally"
#A will not overwrite a

Python Variables

Python is not “statically typed”. We do not need to declare variables before using them or declare their type. A variable is created the moment we first assign a value to it. A variable is a name given to a memory location. It is the basic unit of storage in a program.

Let’s see the simple variable creation:

 #!/usr / bin / python
  
# An integer assignment
age =45
  
# A floating point
salary =1456.8
  
# A string
name ="John"
  
print(age)
print(salary)
print(name)

Output:

 45
1456.8
John

Let’s see how to declare the variable and print the variable.

 # declaring the var
Number =100
  
# display
print( Number)

Output:

 100

We can re-declare the python variable once we have declared the variable already.

 # declaring the var
Number =100
  
# display
print("Before declare: ", Number)
  
# re-declare the var
Number =120.3
    
print("After re-declare:", Number)

Output:

 Before declare:  100
After re-declare: 120.3

Also, Python allows assigning a single value to several variables simultaneously with “=” operators. For example: 

 #!/usr / bin / python
  
a =b =c =10
  
print(a)
print(b)
print(c)

Output:

 10
10
10

Python allows adding different values in a single line with “,”operators.

 #!/usr / bin / python
  
a, b, c =1, 20.2, "GeeksforGeeks"
  
print(a)
print(b)
print(c)

For more, checkout W3Schools and Geeks For Geeks.