我的函数查找列表的平均值有什么问题

Question

我知道有一种更简单的方法可以在不使用for循环的情况下找到列表的平均值，但在这种情况下，我需要使用for循环编写一个函数来找到平均值。

myOddList = [1, 2, 3, 4, 5]
def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
mean = sumOfNumbers / (len(myOddList))
return mean

mean = meanCalculator(myOddList)
print(mean)

当我运行这段代码而不是得到3时，我得到了0.2，所以我知道这一切看起来很简单，但我不知道我做错了什么。

Answer 1

由于在Python中，您必须通过缩进来定义循环的开始和结束时间，因此当您返回当前执行情况的平均值时：

myOddList = [1, 2, 3, 4, 5]
def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
mean = sumOfNumbers / (len(myOddList))
return mean <------- this stops the for loop at the first iteration
and  returns 1 / (len(myOddList)) = 0.2

mean = meanCalculator(myOddList)
print(mean)

但如果你按照以下方式进行操作，它会按预期工作：

myOddList = [1, 2, 3, 4, 5]
def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
mean = sumOfNumbers / (len(myOddList))
return mean <------- this way you return the mean only once the 
for loop is complete and you have found the sum
of all the numbers in the array
mean = meanCalculator(myOddList)
print(mean)

Answer 2

您正在返回for循环中的平均值。它到达第一个数字1，并将其除以5，返回0.2

myOddList = [1, 2, 3, 4, 5]
def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
mean = sumOfNumbers / (len(myOddList))
return mean

mean = meanCalculator(myOddList)
print(mean)

Answer 3

this:

def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers =i+sumOfNumbers
mean = sumOfNumbers / (len(myOddList))
return mean

mean = meanCalculator(myOddList)
print(mean)

您必须处于循环之外--->返回平均

Answer 4

将所有数字相加，然后返回for循环外的平均值。在求和完成之前，不需要在for循环内计算平均值，并且您不希望return在for循环中，或者它在第一个数字上停止。CCD_ 5是另一个优化。

def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
return sumOfNumbers / len(myOddList)

Answer 5

对我来说，这似乎是一个缩进问题，其他一些行缩进过多：

myOddList = [1, 2, 3, 4, 5]
def meanCalculator(myOddList):
sumOfNumbers = 0
for i in myOddList:
sumOfNumbers += i
# Should be outside the loop since
# It doesn't really make sense to keep computing the mean for every iteration of the loop
mean = sumOfNumbers / (len(myOddList))
return mean

mean = meanCalculator(myOddList)
print(mean)

此外，您应该能够使用内置的总和来计算阵列的总和

def meanCalculator(myOddList):
sumOfNumbers = sum(myOddList)
mean = sumOfNumbers / len(myOddList)
return mean

myOddList = [1, 2, 3, 4, 5]
mean = meanCalculator(myOddList)
print(mean)