python 实现求和、计数、最大最小值、平均值、中位数、标准偏差、百分比。
import sys class Stats: def __init__(self, sequence): # sequence of numbers we will process # convert all items to floats for numerical processing self.sequence = [float(item) for item in sequence] def sum(self): if len(self.sequence) < 1: return None else: return sum(self.sequence) def count(self): return len(self.sequence) def min(self): if len(self.sequence) < 1: return None else: return min(self.sequence) def max(self): if len(self.sequence) < 1: return None else: return max(self.sequence) def avg(self): if len(self.sequence) < 1: return None else: return sum(self.sequence) / len(self.sequence) def median(self): if len(self.sequence) < 1: return None else: self.sequence.sort() return self.sequence[len(self.sequence) // 2] def stdev(self): if len(self.sequence) < 1: return None else: avg = self.avg() sdsq = sum([(i - avg) ** 2 for i in self.sequence]) stdev = (sdsq / (len(self.sequence) - 1)) ** .5 return stdev def percentile(self, percentile): if len(self.sequence) < 1: value = None elif (percentile >= 100): sys.stderr.write('ERROR: percentile must be < 100. you supplied: %s\n'% percentile) value = None else: element_idx = int(len(self.sequence) * (percentile / 100.0)) self.sequence.sort() value = self.sequence[element_idx] return value