# Enter a code

d = {'Alice': [50, 61, 66], 'Bob': [80, 61, 66], 'Candy': [88, 75, 90]}

for key in d.keys():

    for score in d[key]:

        print(key, score)

for i in d.items():

    if i[1] <= 60:

        print(i[0])

d = {'Alice': [50, 61, 66], 'Bob': [80, 61, 66], 'Candy': [88, 75, 90]}

for item in d.items():

    for score in item[1]:

        print(item[0] +':' + str(score))

d = {'Alice': [50, 61, 66], 'Bob': [80, 61, 66], 'Candy': [88, 75, 90]}
for key in d:
    print(key)
    value =d[key]
    print(value)

d = {'Alice': [50, 61, 66], 'Bob': [80, 61, 66], 'Candy': [88, 75, 90]}

print(len(d.keys()))

不用循环，d.key()获取所有元素，再len（）获取长度就行了