您如何找到字典中哪个键的值列表最长？

Question

I am attempting to figure out which Key in my dictionary has the longest list of values. I am in a very simple Computer Science class so I cannot use lambda and other complex terms. I'm wondering if there is a way to use loops, if statements, and len to do so?

Also how would I display the value of the key with the longest list of values?

Answer 1

A simple solution can go like this:

max_len = 0
max_key = ""
for key in d:
    cur_len = len(d[key])
    if cur_len>max_len:
        max_key = key
        max_len = cur_len
print max_key

Answer 2

x={'a':[9,8],'b':[1,2,3],'c':'1,2,3,4'}
print [k for k in x.keys() if x[k]==max(x.values(),key=len)]

You can try this.

Answer 3

import itertools

preds = {'lion': ['gazelle', 'zebra', 'antelope'], 'eagle': ['sparrow', 'mouse'], 'crocodile': ['gazelle', 'antelope', 'buffalo', 'zebra']}

byprey = sorted([(len(v), k) for k, v in preds.iteritems()], reverse=True)

num, predator = byprey[0]
print predator

For python 3 you need only change iteritems to items eg

byprey = sorted([(len(v), k) for k, v in preds.items()], reverse=True)

and print is a function

print (predator)