Source code for axelrod.strategies.shortmem

from axelrod import Player
from axelrod.action import Action

C, D = Action.C, Action.D




class ShortMem(Player):
    """
    A player starts by always cooperating for the first 10 moves.

    From the tenth round on, the player analyzes the last ten actions, and
    compare the number of defects and cooperates of the opponent, based in
    percentage. If cooperation occurs 30% more than defection, it will
    cooperate.
    If defection occurs 30% more than cooperation, the program will defect.
    Otherwise, the program follows the TitForTat algorithm.

    Names:

    - ShortMem: [Andre2013]_
    """

    name = "ShortMem"
    classifier = {
        "memory_depth": float("inf"),
        "stochastic": False,
        "long_run_time": False,
        "inspects_source": False,
        "manipulates_source": False,
        "manipulates_state": False,
    }



    @staticmethod
    def strategy(opponent: Player) -> Action:
        """Actual strategy definition that determines player's action."""
        if len(opponent.history) <= 10:
            return C

        array = opponent.history[-10:]
        C_counts = array.count(C)
        D_counts = array.count(D)

        if C_counts - D_counts >= 3:
            return C
        elif D_counts - C_counts >= 3:
            return D
        else:
            return opponent.history[-1]