嵌套 python 字典中的项目总和

Question

I have a nested dictionary

mydict = {
 'school1': {
    'grades1': [78, 96, 80], 
    'grades2' : [81, 86, 90]}, 
 'school2': {
    'grades3' : [60, 65, 70],
    'grades4' : [67, 98, 100]}
} 

I want to find the sums of 'grade' sub dictionary I have and can't quite figure it out. I do not want to hard code

sum(mydict['school1']['grades1'])

and so on.

'for schools in my_dict2:

print(schools)
for grades in my_dict2[schools]:
    print(grades)
    for values in my_dict2[schools][grades]:
        print(sum(values))`

I got to the values, but trying to take the sum of values here results in TypeError: 'float' object is not iterable

Any help much appreciated! Thanks!

Answer 1

Easiest way to loop through dictionaries in python is to use dict.values() , dict.keys() , or its combined cousin dict.items() . So a purely for-loop implementation might look like so:

sumGrades = []
for school in mydict.values():
    sumGrades.append(0)
    for grade in school.values():
        sumGrades[-1] += sum(grade)

And converting to list comprehension:

sumGrades = [sum(sum(g) for g in s.values()) for s in mydict.values()]

Answer 2

I have a nested dictionary

mydict = {
 'school1': {
    'grades1': [78, 96, 80], 
    'grades2' : [81, 86, 90]}, 
 'school2': {
    'grades3' : [60, 65, 70],
    'grades4' : [67, 98, 100]}
} 

I want to find the sums of 'grade' sub dictionary I have and can't quite figure it out. I do not want to hard code

sum(mydict['school1']['grades1'])

and so on.

'for schools in my_dict2:

print(schools)
for grades in my_dict2[schools]:
    print(grades)
    for values in my_dict2[schools][grades]:
        print(sum(values))`

I got to the values, but trying to take the sum of values here results in TypeError: 'float' object is not iterable

Any help much appreciated! Thanks!