Ruby return different type in “array.each”

Question

Please consider this code:

    board = entities.each { |e| return if not findBoard( e ).nil? }

It should do exactly the same as:

    for e in entities
        board = findBoard( e )

        if not board.nil?
            break
        end
    end

but the first one does not work while the second one goes fine.

entities is an array of Entity objects and findBoard() returns a Board object or nil .

Entity and Board are not related classes.

I know that the second code works fine but since I am starting to learn Ruby, I am wondering if it is any more elegant way to do this so I ask, is it possible for an each method to return a different object type other than the objects in array (I guess it should)?

Really thanks.

Answer 1

你可以使用懒惰的枚举器 ：

board = entities.lazy.map { |e| find_board(e) }.detect { |b| b }

Answer 2

尝试：

board = entities.find {|e| b = findBoard(e) and break b }

Answer 3

There is unfortunately no perfectly clean way of doing this in Ruby. I'd suggest the mildly ugly

board = nil
entities.find { |e| board = findBoard( e ) }
board

find will work the same as each except that it will short-circuit as soon as board is set to a non-nil value.

Answer 4

board = nil
entities.each { |e| board = findBoard(e) ; break unless board.nil?}