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Apply method to each elements in array/enumerable

Asked 2011-06-27T17:58:00.277
54

This is my array:

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

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

How can I do this (converting each element of the enumerable to something else)?

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2 Answers

20

You can use map or map! respectively, the first will return a new list, the second will modify the list in-place:

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

>> array.map{ |x| x.to_s }
=> ["one", "two", "three"]
answered 2011-06-27T18:01:41.923
17

It's worth noting that if you have an array of objects you want to pass individually into a method with a different caller, like this:

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

You can use the method method combined with block expansion behavior to simplify:

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

If you're not familiar, what method does is encapsulates the method associated with the symbol passed to it in a Proc and returns it. The ampersand expands this Proc into a block, which gets passed to map quite nicely. The return of map is an array, and we probably want to format it a little more nicely, hence the join.

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

answered 2011-07-27T15:51:00.503

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