查找列表python的总平均列表

Question

I am new to python, and I need help with finding averages, variances, and grand average in a list of lists. I have a list of lists like this:

allgroups = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]

and I am able to find the averages and variances, but for the grand average, I have a problem to find the solution: here is my code:

def avg(allgroups):
    return [float(sum(i)) / len(i) for i in allgroups]


def variance(allgroups):
    return [sum((x - sum(group) / len(group)) ** 2 for x in group) / (
                len(group) - 1) for group in allgroups]


def calcavg(allgroups):
    return float(sum(avg(allgroups) / len(avg(allgroups))))

TheAvg = avg(allgroups)
print(TheAvg)
Variance = variance(allgroups)
print(Variance)
calcAvg = calcavg(allgroups)
print(calcAvg)

I keep getting the screen error:

return float(sum(avg(allgroups) / len(avg(allgroups))))

TypeError: unsupported operand type(s) for /: 'list' and 'int'

When I do the code:

average= sum(TheAvg)/len(TheAvg)

I could find the grand average, but when I do

def calcavg(allgroups):
    return float(sum(avg(allgroups) / len(avg(allgroups))))

I keep getting an error. I will be grateful for any help. P/S: I can't use any library for this problem such as numpy or statistic.

Answer 1

You have a typo in your calcavg function. You did not properly inclose the sum operator on the left-hand side. The function should be as shown below:

def calcavg(allgroups):
    return float(sum(avg(allgroups)) / len(avg(allgroups)))

calcavg(allgroups)

>> 6.5