Question

I’m new to ruby world and i’m currently studying it. I have read over the google about nil object, but still can`t figure out what it is ?

Can anyone explain me in more details or share some link for further reading ?

Answer 1

nil is the one and only instance of the NilClass class. It doesn’t have any special behavior (other than the fact that it’s interpreted as false in a boolean context (e.g. in an if condition), as Andrew Grimm helpfully pointed out). The purpose of nil is to signify “no result”.

For example a method which is supposed to find an item meeting a certain condition would return nil if there is no item that meets the condition. Or accessing the ith element of an array which has less than i elements will return nil.

It has a similar purpose to the null pointer in other languages, except that you can call Object methods (i.e. methods which are defined on every object) on it without causing an exception.