CODEWITHSUNDEEP
pythongeneratoryield
Goulash
Goulash

Reputation: 3838

Replacing yield with returns in recursive code

How would I remove the yield statements in this code, and instead use it as a normal function with return statements?

def solve(game_board):
   num_occupied, board_layout=game_board
   if num_occupied < 2:
     yield (None, game_board)
   else:
     for move in possible_moves():
       new_game_board = do_move(game_board, move)
       if new_game_board:
         for item in solve(new_game_board):
           solved_num_occupied, solved_game_board = item 
           yield (move, solved_num_occupied), solved_game_board

The solver is for a triangular game of peg solitaire, with 15 indices. The game_board structure is a tuple, containing the number of occupied spaces on the board and an array with 15 elements, containing 1 or 0 depending on whether there is a peg there.

I have tried my best by storing the (move, solved_num_occupied), solved_game_board in an array and returning them after one of the for loops, but it always comes out empty. I think I just don't really understand how the generator operates, and where it terminates. Any help would be much appreciated!

Here is the full code, if needed (note: I changed the variable names in the function before putting it here to make it more understandable): https://pastebin.com/raw/dEyLY2SH

Upvotes: 2

Views: 771

Answers (1)

cs95
cs95

Reputation: 402363

Accumulate everything at once and return, instead of yielding one at a time. Like I said in my comment, just replace every yield call with a call to list.append. 

def solve(game_board):
  # Initialise your list.
  moves = []
  num_occupied, board_layout=game_board
  if num_occupied < 2:
    # First change.
    moves.append((None, game_board))
  else:
    for move in possible_moves():
      new_game_board = do_move(game_board, move)
      if new_game_board:
        for item in solve(new_game_board):
          solved_num_occupied, solved_game_board = item 
          # Second change
          moves.append(((move, solved_num_occupied), solved_game_board))
  # Final change.
  return moves

Upvotes: 1

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