tank.py

from collections import Counter

class Tank():
    def __init__(self,value):
        self.tab = dict(Counter(value))

    def Values(self):
        return self.tab.keys()

    def Mult(self, x, factor):
        self.tab[x] = self.tab.get(x, 0) * factor

    def Likelihood(self, data, hypo):
        if hypo < data:
            return 0
        else:
            return 1.0/hypo

    def Normalize(self, fraction=1.0):
        total = sum(self.tab.itervalues())
        factor = float(fraction) / total
        for x in self.tab:
            self.tab[x] *= factor
        return sum(self.tab)

    def Update(self, data):
        for hypo in self.Values():
            like = self.Likelihood(data, hypo)
            self.Mult(hypo, like)
        return self.Normalize()

    def Print(self):
        for val, prob in sorted(self.tab.iteritems()):
            print val, prob

def main():
    suite = Tank([500, 1000, 1500, 2000, 3000])
    for roll in [4, 180, 75, 1007, 1003, 1500]:
        suite.Update(roll)
    print 'After more obs'
    suite.Print()

if __name__ == '__main__':
    main()