Another Look at puts

There’s something strange about our favorite method. Take a look at this:

Why do these three all print the same thing? Well, the last two should, since 20.to_s is '20'. But what about the first one, the integer 20? For that matter, what does it even mean to write the integer 20? When you write a 2 and then a 0 on a piece of paper, you are writing a string, not an integer. The integer 20 is the number of fingers and toes I have; it isn’t a 2 followed by a 0.

Well, here’s the big secret behind our friend puts: before puts tries to write out an object, it uses to_s to get the string version of that object. In fact, the s in puts stands for string; puts really means put string.

This may not seem too exciting now, but Ruby has many, many kinds of objects (you’ll even learn how to make your own), and it’s nice to know what will happen if you try to puts a really weird object, such as a picture of your grandmother or a music file or something. It’ll always be converted to a string first. But that will come later. In the meantime, we have a few more methods for you, and they allow us to write all sorts of fun programs.