Variables

storing values into named spaces

In mathematics, we learn in algebra that variables are symbols that store values ... the same happens in computer programming!

Declaring variables

In Python, we simply start with a variable name and attach a value to it, separated by =:

meaningful_variable_name = "This is a very meaningful value!"

The value would have either a pair of single quotes or double quotes...

... and there we have it: a variable name equivalent to a value!

We have no need to place a keyword before the variable name (like in JavaScript or Java) - just declare away!

Rules for variable names in Python

• must begin with a letter (a-z)

• must not start with a digit (0-9) but may contain them

  • e.g. route66 but not 5alive

• can include an underscore (_)

  • e.g. meal_time

Using variables

Let's use the variable by printing its name (without quotation marks) to output its value:

meaningful_variable_name = "This is a very meaningful value!"
print(meaningful_variable_name)

Output:

This is a very meaningful value!

Note that if the variable has no value, it will throw an error!