statistics.py 文件源码

def append(self, x):
        self._count += 1

        if self._count == 1:
            self.m = x
            self.last_m = x
            self.last_s = 0.0
            self.min = x
            self.max = x
        else:
            self.m = self.last_m + (x - self.last_m) / self._count
            self.s = self.last_s + (x - self.last_m) * (x - self.m)

            self.last_m = self.m
            self.last_s = self.s

            self.min = numpy.minimum(self.min, x)
            self.max = numpy.maximum(self.max, x)