Python学习（五）

来源：互联网发布：linux windows双系修复编辑：程序博客网时间：2024/06/05 17:38

都知道方差，标准差是怎么回事，所以就用一个列表存储班级学生的成绩，对这些成绩求和值，平均值，方差以及标准差。对每一个值都用函数来求得。

grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]def print_grades(grades):    for grade in grades:        print grade#计算成绩总和def grades_sum(grades):    total = 0    for grade in grades:         total += grade    return total#计算平均值    def grades_average(grades):    sum_of_grades = grades_sum(grades)    average = sum_of_grades / float(len(grades))    return average#计算方差def grades_variance(scores):    average=grades_average(scores)    variance=0    for score in scores:        variance+=(average-score)**2    result=variance/len(scores)    return resultprint grades_variance(grades)#计算标准差def grades_std_deviation(variance):    return variance**0.5    variance=grades_variance(grades)print print_grades(grades)print grades_sum(grades)print grades_average(grades)print grades_variance(grades)print grades_std_deviation(variance)

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