Python 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)

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

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

Example

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

You will learn more about data types and casting later in this tutorial.

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

Example

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

Variable names are case-sensitive.

Example

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

Python allows you to assign values to multiple variables in one line:

Example

x, y, z = "Orange", "Banana", "Cherry"
print(x)
print(y)
print(z)

Note: Make sure the number of variables matches the number of values, or else you will get an error.

And you can assign the same value to multiple variables in one line:

Example

x = y = z = "Orange"
print(x)
print(y)
print(z)

If you have a collection of values in a list, tuple etc. Python allows you to extract the values into variables. This is called unpacking.

Example: Unpack a list:

fruits = ["apple", "banana", "cherry"]
x, y, z = fruits
print(x)
print(y)
print(z)

You will learn more about unpacking, and lists/tuples, in later chapters.