Slide 23
Slide 23 text
23
© Link and Motivation Group
# Before
name = "持部 太郎"
users = User.all
user_by_name =
users.index_by(&:name)
user_id = user_by_name[name].id
②不要に大きなインスタンス生成をしている
# After
name = "持部 太郎"
users = User.all.pluck(:id, :name)
user_by_name =
users.index_by(&:name)
user_id = user_by_name[name][0]
users user_by_name
Before ActiveRecord::Relation valueがActiveRecordのHash
After Array valueがArrayのHash