Ruby on Rails, create an instance variable from another instance variable's property

Question

I think this is an easy question but I can't seem to wrap my head around it to solve it. I want to create an instance variable from a property of another instance variable. For example:

@posts = Post.find(:all, :conditions => ['day > ?', Date.today], :order => 'day')

I want to get another instance variable that contains all of the dates from the @posts. Is there a way of quickly getting it without having to create a helper/function? Thanks!

Wayne Conrad · Accepted Answer · 2011-06-20 04:36:25Z

3

@posts.map(&:day)

which is a shorthand for

@posts.map do |post|
  post.day
end

The result is an array of the value of each post.day

answered Jun 20, 2011 at 4:36

Wayne Conrad

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1 Comment

Marco A Over a year ago

Thanks, it's been great to me so far =)

Roland Mai · Accepted Answer · 2011-06-20 04:40:48Z

0

What Wayne has is a appropriate. I prefer collect instead of map, but they are equivalent.

@dates = @posts.collect{|post| post.day}.uniq

Notice, uniq at the end will give you the unique values.

answered Jun 20, 2011 at 4:40

Roland Mai

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