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Ruby Ruby Objects and Classes Variables and Methods The to_s method

lindseyk
lindseyk
4,506 Points
Posted by lindseyk
lindseyk
4,506 Points

I'm not totally clear on the reason one should create a to_s method?

In what causes would one want to print the name of an instance as a string, rather than just having a name attribute? Maybe I'm not fully understanding the function?

1 Answer

Andrew Stelmach
Andrew Stelmach
12,583 Points
Andrew Stelmach
Andrew Stelmach
12,583 Points

In the video he creates a variable called name that is assigned to an instance of the Name class: Name.new.

He then calls puts on it: puts name. This prints the name object as a String; it's a funny looking object that isn't very useful.

puts uses the in-built Ruby method: to_s. In this case, the result of using it is not producing anything desirable, so Jason chooses to override the to_s method, by defining it in his Name class.

Then, when puts name is executed, Ruby uses the custom to_s method that has just been defined, rather than the native in-built one. This produces a result that is more desirable to Jason.

lindseyk
lindseyk
4,506 Points
lindseyk
lindseyk
4,506 Points

Ah, I understand now that he is overriding the existing to_s. That makes sense. Thanks!! Is there a reason that is preferable to doing something like this?

Class Dog

attr_reader :name

def initialize(name) @name = name

some more methods and such down here...

end end

fido = Dog.new("Fido")

puts fido.name

or maybe

puts "Hey, there's #{fido.name}!"

(Sorry for the very strange formatting of this response! I'm writing from an iPad and can't figure out how to insert a code sample... Also, my published comment isn't keeping new lines, tabs, etc in the way I'm writing them. )