ruby Rails'index_by：将数组转换为哈希的简便方法

Posted 2021-05-16

Post.all.index_by { |post| post.id }
# => { 1 => #<Post ...>, 2 => #<Post ...>, ... }

Post.all.index_by(&:title)
# => { "My first post" => #<Post ...>, "My second post" => #<Post ...>, ... }