Variables

A variable is a symbol that refers to an object, such as a string, integer, or list. If you’re not already at the Python prompt, open your terminal and type python at the $. You’re in the right place when you see >>>.

Try these commands in order:

>>> x = 5
>>> x
5
>>> x + 10
15
>>> y = "hello"
>>> y
'hello'
>>> y + " and goodbye"
'hello and goodbye'

As you can see above, the = sign lets you assign symbols like x and y to data.

Variables can be longer words as well:

>>> breakfast = ['ham', 'eggs', 'toast']
>>> breakfast
['ham', 'eggs', 'toast']
>>> type(breakfast)
<class 'list'>

Variables can have letters, numbers, and underscores, but should start with a letter.

If you are curious about learning more about naming conventions for variables, you can check out the PEP8 style guide’s section on Naming Conventions. PEP8 is the widely accepted guide for Python programmers everywhere.

Challenge

So I just told you that variables shouldn’t start with a number or an underscore. What does that even mean? Will your computer explode if you write 3_flower = "buttercup"?

Only one way to find out. Try giving weird names to variables and see if you can learn a bit about the rules.

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