Python:使用循环计算列表中值的标准差

Question

我正在尝试根据列表中的值计算标准差，但收到错误:

def mean(list):
    return sum(list)/len(list)

std_deviation = (sum([(list - mean(list)) ** 2 for number in list]) / (len(list) - 1)**(1/2)

print(std_deviation)

Answer 1

您的括号设置错误，您需要的不是 list -mean(list)，而是 number -mean(list)

固定版本(没有名称list，因为它是内置的):

def mean(values):
    return sum(values)/len(values)

my_list = [1,2,2,3,4,5,5,8]

std_deviation = (1/(len(my_list) - 1) * sum((number - mean(my_list))**2 for number in my_list))**.5
print(std_deviation)  # prints 2.2519832529192065