Ruby on Rails turn each iteration into an array

Question

I feel like this is such an easy question

<% @state.cities.each do |city| %>
   <%= city.id %>
<% end %>

puts the ids as follows:

1
2
3 etc...

How do I turn the iteration into an array?

so it outputs as follows:

[1,2,3,4,etc...]

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– Graham Slick, Commented Dec 13, 2016 at 22:09

frank184 · Accepted Answer · 2016-12-13 21:25:18Z

3

There is a method that does just that!

What you are looking for is the map method.

Creates a new array containing the values returned by the block.

The documentation states, creates an array containing the values returned by a block.

@state.map do |state|
  state.id
end
=> [1,2,3,...]

Which is the same as:

@state.map(&:id)
=> [1,2,3,...]

But uses the Ruby Enumerable shorthand.

answered Dec 13, 2016 at 21:10

frank184

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Comments

Ronan Lopes · Accepted Answer · 2016-12-13 21:02:13Z

2

@state.map(&:id) would give you the same result!

answered Dec 13, 2016 at 21:02

Ronan Lopes

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spickermann · Accepted Answer · 2016-12-13 21:18:47Z

2

You can use map:

<%= @state.map(&:id) %>

answered Dec 13, 2016 at 21:02

spickermann

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