I'm looking for an easy/fast way of getting an array of ids from a Active Record relation.
Currently i have:
product_ids = Product.select(:id).where(:colour => 'blue').all.map{|p|p.id}
But that's messy and requires a map..
Something like this would be cooler:
product_ids = Product.where(:colour => 'blue').ids
Any ideas?
Thanks :)
A little bit more neat solution:
Product.where(:colour => 'blue').pluck(:id)
In recent versions of Rails the ids method can be used.
Product.where(color: 'blue').ids
Have been reading through the rails 4 docs and it looks like they support the ids method that I said would be cool in the question now.
http://api.rubyonrails.org/classes/ActiveRecord/Calculations.html#method-i-ids
Nice to know the team are reading my mind :)
To build on the previous answers, if you are working through an association, you can just append _ids to the query.
So in your example, if a Supplier has_many Products, then:
supplier.product_ids
would return your array of product ids that belongs to the supplier.
map{|p| p.id}can you writemap(&:id). This is true for all enumerators (each,any?,select,rejectetc.), and will call the symbol on each object it loops through.map(&:id)just had a mental blank when writing this up :P