Machine learning for humans - What is machine learning 02 - www.tinymind.ai

ml.py

class FlipPredictor(object):

    def __init__(self):
        self.tries = 0  # Total tries so far.
        self.guess = 5  # Current guess.

    def predict(self, previous):
        """Predict # heads in the next 10 flips.
        
        previous is # heads in the previous 10 flips. That's what we learn from!
        """
        # The first guess is a blind guess. No previous flips yet!
        if previous is None:
            self.tries = 1
            return self.guess

        # Modify our guess by computing the weighted average of our existing
        # guess and the # heads of the latest flips.
        self.guess = (self.guess * self.tries + previous) / (self.tries + 1)
        self.tries = self.tries + 1
        return self.guess
    
predictor = FlipPredictor()
predictor.predict(None)  # first guess is blind, predicts 5
predictor.predict(8)     # 8 heads in last 10, predicts 6.5
predictor.predict(7)     # 7 heads in last 10, predicts 6.67
predictor.predict(8)     # 8 heads in last 10, predicts 7
predictor.predict(9)     # 9 heads in last 10, predicts 7.4
predictor.predict(8)     # 8 heads in last 10, predicts 7.5