Apply method to each element in array / enumerable

Question

This is my array:

array = [:one,:two,:three] 

I want to apply the to_s method to all my array elements in order to get array = ['one','two','three'] .

How can I do this (converting each element of an enumerable to another)?

Answer 1

This will work:

 array.map!(&:to_s) 

Answer 2

It is worth noting that if you have an array of objects that you want to pass individually to a method with another caller, for example:

 # erb <% strings = %w{ cat dog mouse rabbit } %> <% strings.each do |string| %> <%= t string %> <% end %> 

To simplify, you can use the method method in combination with the behavior of the block extension:

 <%= strings.map(&method(:t)).join(' ') %> 

If you don't know what method does, it encapsulates the method associated with the character passed to it in Proc and returns it. Ampersand extends this Proc to a block that is pretty well passed to map . The return map is an array, and we probably want to format it a little nicer, hence join .

The caveat is that, as with Symbol#to_proc , you cannot pass arguments to the helper method.

Answer 3

You can use map or map! accordingly, the first will return a new list, the second will change the list in place:

 >> array = [:one,:two,:three] => [:one, :two, :three] >> array.map{ |x| x.to_s } => ["one", "two", "three"] 

Answer 4

• array.map!(&:to_s) changes the source array to ['one','two','three']
• array.map(&:to_s) returns an array ['one','two','three'] .