记录以grades列表为例，分别定义输出、求和、平均值、方差和标准差函数，并输出相应的值
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]#定义输出函数defPRint_grades(grades):forgradeingrades:printgrade#定义求和函数defgrades_sum(grades):
total=0forgradeingrades:
total+=gradereturntotal#定义求平均值函数defgrades_average(grades):
sum_of_grades=grades_sum(grades)
average= sum_of_grades /float(len(grades))returnaverage#定义求方差函数defgrades_variance(scores):
average=grades_average(scores)
variance=0forscoreinscores:
variance+=(average-score)**2returnvariance/len(scores)#定义求标准差函数defgrades_std_deviation(variance):returnvariance**0.5variance=grades_variance(grades)#调用函数分别输出对应的值printprint_grades(grades)printgrades_sum(grades)printgrades_average(grades)printgrades_variance(grades)printgrades_std_deviation(variance)