出现“浮动对象不可迭代”错误

Question

所以我正在尝试使用python来做方程函数

这是我的代码：

def var_method_1(x):
    n = len(x)
    return [sum(i**2)-1/n*(sum(i)**2) for i in x]/(n-1)

所以这是调用代码，这是很长的调用代码，不确定是哪个部分导致了错误

# Test cell: `exercise_1_test`

from random import gauss
from statistics import variance

n = 100000
mu = 1e7
sigma = 1.0

for _ in range(5): # 5 trials
    X = [gauss(mu, sigma) for _ in range(n)]
    var_py = variance(X)
    try:
        del variance
        var_you_0 = var_method_0(X)
        var_you_1 = var_method_1(X)
    except NameError as n:
        if n.args[0] == "name 'variance' is not defined":
            assert False, "Did you try to use `variance()` instead of implementing it from scratch?"
        else:
            raise n
    finally:
        variance = SAVE_VARIANCE

    rel_diff_0 = abs(var_you_0 - var_py) / var_py
    rel_diff_1 = abs(var_you_1 - var_py) / var_py
    print("\nData: n={} samples from a Gaussian with mean {} and standard deviation {}".format(n, mu, sigma))
    print("\tPython's variance function computed {}.".format(var_py))
    print("\tvar_method_0(X) computed {}, with a relative difference of {}.".format(var_you_0, rel_diff_0))
    assert rel_diff_0 <= n*(2.0**(-52)), "The relative difference is larger than expected."
    print("\tvar_method_1(X) computed {}, with a relative difference of {}.".format(var_you_1, rel_diff_1))
    assert rel_diff_1 > n*(2.0**(-52)), "The relative difference is smaller than expected!"

print("\n(Passed!)")

这是错误：

Answer 1

错误的回报。

return (sum([i**2 for i in x]) - sum(x)**2/n)/(n-1)

Answer 2

sum采用可迭代方式，例如列表求和。在这种情况下，您给sum设置了一个浮点数（假设x是您对x进行迭代时的浮点数向量）。