From GMod Wiki
Booleans are simple types of data, they can either be true or false.
If you know something is a boolean, you can check if it's true / false like so:
if myBool then --This code will run if myBool is true else --This code will run if myBool is false end
When a variable is given by itself in an if statement, or is used with a logical operator like !, and, or, etc, or is otherwise used in a situation where it only makes sense to use true / false values, Lua evaluates the variable to (looks at it's value, then returns) true or false. If a variable is equal to nil or false, Lua evaluates it to false. Otherwise, Lua evaluates it to true.
local hello = "hi"; local num = 0; local haveWeapon = false; --evals to true if hello then Msg( "hello evaluated to true\n" ); end --evals to true if num then Msg( "num evaluated to true\n" ); end --evals to false if haveWeapon then Msg( "haveWeapon evaluated to true" ); end --doesNotExist is nil, will eval to false if doesNotExist then Msg( "doesNotExist evaluated to ture" ) end
A quick way of setting a variable depending on a boolean is to use and/or.
str = godmode and "Godmode on" or "Godmode off"
str will be "Godmode on" if godmode is true, otherwise "Godmode off"