python字典怎么比较值

先建立一个字典，比如：phoneNumbers =?

{'Bob': '444-4321', 'John': '555-1234', 'Mary': '555-6789', 'Jenny': '867-5309'}

按照值的大小顺序排列

for value in sorted(phoneNumbers.values()):

for key in phoneNumbers.keys():

if phoneNumbers[key] == value:

print key, phoneNumbers[key]