CODEWITHSUNDEEP
rubyarraysruby-on-rails-3.2
Douglas
Douglas

Reputation: 5349

How to retrieve an array of values from an array of ActiveRecord objects with 'each' method?

I'm trying to perform this non-basic query with Rails :

proj_repartitions = ProjRepartition.includes(:proj_contributions).find( proj_project.proj_charges.each{|pc| pc.proj_repartition_id} )

The point is I need to pass an array of 'ids' to the find method. I want to extract those 'ids' from an array of ActiveRecord objects where each of these is equipped with an 'id' attribute.

When I try on the Rails console:

proj_project.proj_charges.each{|pc| pc.proj_repartition_id}

I got exactly the same array as proj_project.proj_charges

What am I doing wrong?

=== UPDATE ===

According to the answers, my definitive working code is: 

proj_project.proj_charges.collect{|pc| pc.proj_repartition_id}

Upvotes: 0

Views: 164

Answers (3)

Intrepidd
Intrepidd

Reputation: 20868

proj_project.proj_charges.map(&:proj_repartition_id)

Short way of writing

proj_project.proj_charges.map{|pc| pc.proj_repartition_id}

Upvotes: 1

Richard Lau
Richard Lau

Reputation: 696

Each only executes the do block code for each item but doesn't "save" the return value.

Collect and Map executes the do block code for each item and the return value in an array.

hope that makes sense

Upvotes: 1

Dave Sexton
Dave Sexton

Reputation: 11188

Instead of using each try map or collect - they should return an array.

Upvotes: 1

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