Variables

2.2. Variables#

2.2.1. Introduction#

Python stores data in variables. To assign data to a variable we use the = sign.

For example,

x = 'Alison'

One way to think of variables is to treat them like a box. In the above example, we have a box named x, and the box is storing the value 10.

../../_images/variable_in.png

When we want to use the value x, we look for the box labelled x and extract the contents.

../../_images/variable_out.png

Here is an example:

x = 'Alison'
print(x)

Note that the variable x does not have quotes but the string ‘Alison’ does!

2.2.2. Types#

Python has different types of variables. Here are some of the most commonly used variables.

  • integer: a whole number

    • x = 5

    • num = 21

  • float: a decimal number

    • cost = 1.50

    • pi = 3.14159

  • string: text

    • name = 'steve'

    • message = "great job"

Note

You can use either single quotes ' ' or double quotes " " to indicate a string as long as you start and end with the same type.

  • char: a single character

    • letter = 'a'

    • symbol = '@'

Note

Python does not distinguish between characters and strings and will treat a single character as a string. But other languages will treat them differently!

If you want to know the type of a certain variable, we can use the type function.

print(type(3))
print(type(3.0))
print(type('3'))

<class 'int'>
<class 'float'>
<class 'str'>
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