python 基础 字典 小例子

统计单词次数 作为字典存储

cotent = "who have an apple apple is free free is money you know"
result = {}
for s in content.split(""):
    if s in result:
        result[s] + =1
    else:
        result[s] = 1
print result

反转上面的结果
res = {}
for k,v in result.items():
　　res.setdefault(v,[])
　　res[v].append(k)