How to pull out attributes from a collection into an array

Question

If I have a class that looks like below, how to I pull out just the last name from each instance a collection into an array?

class Person
  include :Mongoid::Document

  field :first_name
  field :middle_name
  field :last_name
  field :email_address

end

Person.all # What do I do after I have the collection?

score 1 · Answer 1 · answered Mar 29 '12 at 18:29

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Person.all.map(&:last_name) will do it

answered Mar 29 '12 at 18:29

cpjolicoeur

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score 0 · Accepted Answer · edited May 23 '17 at 10:08

0

To return an array from a collection:

Person.where(blah).collect(&:last_name)

An explanation of &:object

edited May 23 '17 at 10:08

Community

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answered Mar 29 '12 at 18:26

John Paul Ashenfelter

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score 0 · Answer 3 · answered Mar 29 '12 at 18:30

0

Person.where(...search...).only(:last_name)

http://mongoid.org/docs/querying/criteria.html#only

answered Mar 29 '12 at 18:30

Mike

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How to pull out attributes from a collection into an array

3 Answers3