三种方法：

①直接使用dict

②使用defaultdict

③使用Counter

 ps:`int()`函数默认返回0

 ①dict

text = "I'm a hand some boy!"
frequency = {}
for word in text.split():
  if word not in frequency:
    frequency[word] = 1
  else:
    frequency[word] += 1

 ②defaultdict

import collections
frequency = collections.defaultdict(int)
text = "I'm a hand some boy!"
for word in text.split():
  frequency[word] += 1

 ③Counter

import collections
text = "I'm a hand some boy!"
frequency = collections.Counter(text.split())

总结