获取嵌套字典中字典中键的平均值

Question

假设我想得到所有“Jazz”键的平均值，但是，我想对嵌套字典中的每个单独键都这样做

def average_ratings(aDict) :
    for key in aDict :
        if "Jazz" in aDict:
            mySum = 0
            numNums = 0
            while value in aDict['Jazz'] :
                mySum = mySum + value
                numNums = numNums + 1
            jazzValue = mySum / numNums
            return jazzValue
        if "Rock" in aDict :
            summ = 0
            num = 0
            while value in aDict["Rock"] :
                summ = summ + 1
                num = num + 1
            rockValue = summ / num
            return rockValue

这是我正在翻阅的字典

{'Justin Trudeau': {'Hits': 4, 'Jazz': 3, 'Rock': 7, 'Reggae': 7, 'Dance': 7, 'Blues': 6, 'Rap': 4}, 'Bob Jones': {'EDM': 4, 'Dance': 3, 'Hits': 1, 'Rock': 3, 'Opera': 4, 'Funk': 3, 'Soul': 6, 'Metal': 8, 'Classical': 9}, 'Sam Frizzel': {'Rap': 7, 'Hits': 6, 'Soul': 2, 'EDM': 5, 'Pop': 3, 'Reggae': 3, 'Hip Hop': 5}, 'Captain Nemo': {'Dance': 4, 'Rock': 2, 'Classical': 10, 'World': 8, 'Jazz': 9, 'Hip Hop': 6, 'Soul': 4, 'Metal': 2}}

Answer 1

In [33]: a = {'Justin Trudeau': {'Hits': 4, 'Jazz': 3, 'Rock': 7, 'Reggae': 7, 'Dance': 7, 'Blues': 6, 'Rap': 4}, 'Bob
    ...:  Jones': {'EDM': 4, 'Dance': 3, 'Hits': 1, 'Rock': 3, 'Opera': 4, 'Funk': 3, 'Soul': 6, 'Metal': 8, 'Classica
    ...: l': 9},'Sam Frizzel': {'Rap': 7, 'Hits': 6, 'Soul': 2, 'EDM': 5, 'Pop': 3, 'Reggae': 3, 'Hip Hop': 5}}
    ...:

In [34]: jazz = [a[i].get('Jazz',0) for i in a if 'Jazz' in a[i]]

In [35]: print(sum(jazz)/len(jazz))
3.0

更新：

from collections import defaultdict

a = {'Justin Trudeau': {'Hits': 4, 'Jazz': 3, 'Rock': 7, 'Reggae': 7, 'Dance': 7, 'Blues': 6, 'Rap': 4}, 'Bob Jones': {'EDM': 4, 'Dance': 3, 'Hits': 1, 'Rock': 3, 'Opera': 4, 'Funk': 3, 'Soul': 6, 'Metal': 8, 'Classical': 9}, 'Sam Frizzel': {'Rap': 7, 'Hits': 6, 'Soul': 2, 'EDM': 5, 'Pop': 3, 'Reggae': 3, 'Hip Hop': 5}, 'Captain Nemo': {'Dance': 4, 'Rock': 2, 'Classical': 10, 'World': 8, 'Jazz': 9, 'Hip Hop': 6, 'Soul': 4, 'Metal': 2}}

avgs = defaultdict(list)

for k,v in a.items():
    for i in v:
        avgs[i].append(v[i])
    
for k,v in avgs.items():
    print(f"Average of {k} is {sum(v)/len(v)}")

输出：

Average of Hits is 3.6666666666666665
Average of Jazz is 6.0
Average of Rock is 4.0
Average of Reggae is 5.0
Average of Dance is 4.666666666666667
Average of Blues is 6.0
Average of Rap is 5.5
Average of EDM is 4.5
Average of Opera is 4.0
Average of Funk is 3.0
Average of Soul is 4.0
Average of Metal is 5.0
Average of Classical is 9.5
Average of Pop is 3.0
Average of Hip Hop is 5.5
Average of World is 8.0