variables names for values

A variable is a name for a remembered value.

You can create your own variables using =. You need to define your variables before you can ask the comptuer to use them.

Storing a Number

Once you have defined a variable, you can refer to the value by name anywhere in your program.

x = 2.875
write x * x * x

The single equals = assigns or changes a variable value. Be sure to not try to use = to test equality, because it will change your variable instead of testing it. Tests are done with is.

Variable Names and Strings

A variable can also remember any word or other sequence of characters, called a string.

song = "GEC"
write song
play song + song

Here song is a name for the sequence of letters "GEG". Notice that song is unquoted and "CEG" is quoted. If we wanted to literally write the word "song", then we would have had to use quotes: write "song".

A quoted value is called a literal value: it should not be confused with a variable name, which is unquoted.

Built-in Variables

Built-in names such as as red, pen, dot, play, Turtle, and write, are variables that are predefined by the system before your program runs.

It is best to avoid using these names for your own variables, because when you redefine these variables, their built-in meaning may become unavailable in your program.

Other Types of Values

Variables can take on values that are more complex than numbers and strings: they can also be arrays, objects, or functions.