return arrays as array of 2 elements instead of 4 ruby

Question

I have a simple each statement on an array

game.each{|match|  winner += rps_game_winner(match) 

winner is previously defined as winner = []

rps_game_winner will return an array of 2 elements. I want the winner to be and array of an array of 2 elements. instead if game has 2 matches i will get an array for 4 elements.

Is there a way to quickly convert an array of 4 elements to an array with 2 arrays of 2 elements. Or to make winners an array of 2 elements in the first place

for example winners should equal [["rob","Hi"],["sally","no"]] instead of ["rob","Hi","sally","no"]

Answer 1

Don't use +=; use <<:

game.each{|match| winner << rps_game_winner(match)}

While + combines two arrays into one, << adds new elements. If a new element happens to itself be another array, it's still added as an element, not merged in.

If you prefer words to punctuation, you can also spell it push:

game.each do |match| winner.push(rps_game_winner match) end

Answer 2

Use each_cons, which means each consecutive elements:

game.each_cons(2){|match1,match2| 
    winner << [rps_game_winner(match1), rps_game_winner(match2)]
}

*NB: the use of each_cons works fine if rps_game_winner would return a flat element, not an array with two elements