Module 2 · Variables · Lesson 1 of 8

Variables — data-shaped boxes

So far your values have been throwaway — printed once and gone. A variable lets you keep one: it's a named box that stores a value so you can use it again later, or change it as your program runs.

Two things make a variable: a name on the outside and a value inside. And here's the “data-shaped” part — Python doesn't lock a box to one type. The same name can hold an integer now, a string later, a boolean after that. The box quietly takes the shape of whatever you put in it.

That flexibility is powerful, and just occasionally a trap (a box you thought held a number might now hold text). For the next few lessons we'll keep it simple: how to name a box, how to fill it, and how to use what's inside.