Learn to Program, 2nd Edition

Another Look at puts

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

puts  20
puts  20.to_s
puts '20'

20
20
20

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 ...