Question

Is there a shorter way to do the following (

@user.employees.map { |e| { id: e.id, name: e.name } }
# => [{ id: 1, name: 'Pete' }, { id: 2, name: 'Fred' }]

User has_many employees. Both classes inherit from ActiveRecord::Base.

Two things I don’t like about the above

1. It loads employees into memory before mapping,
2. It’s verbose (subjective I guess).

Is there a better way?

Answer 1

UPDATE:

see @jamesharker’s solution: from ActiveRecord >= 4, pluck accepts multiple arguments:

@user.employees.pluck(:id, :name)

PREVIOUS ANSWER:

for a single column in rails >= 3.2, you can do :

@user.employees.pluck(:name)

… but as you have to pluck two attributes, you can do :

@user.employees.select([:id, :name]).map {|e| {id: e.id, name: e.name} } 
# or map &:attributes, maybe

if you really need lower-level operation, just look at the source of #pluck, that uses select_all