The Book of Ruby

Why Use Symbols?

Some methods in the Ruby class library specify symbols as arguments. Naturally, if you need to call those methods, you are obliged to pass symbols to them. Other than in those cases, however, there is no absolute requirement to use symbols in your own programming. For many Ruby programmers, the “conventional” data types such as strings and integers are perfectly sufficient. However, many Ruby programmers do like to use symbols as the keys into hashes. When you look at the Rails framework in Chapter 19, for example, you will see examples similar to the following:

{ :text => "Hello world" }

Symbols do have a special place in “dynamic” programming, however. For example, a Ruby program is able to create a new method at runtime by calling, ...