第三次
str='''Baby, baby, baby nooo My baby, baby, baby noo My baby, baby, baby nooo I thought youd always be mine mine Baby, baby, baby nooo My baby, baby, baby noo My baby, baby, baby nooo''' print(str); print(str.lower()); print(str.split()) print("统计每个单词出现的次数为:") strSet=set(str.split()) for word in strSet: print(word,str.split().count(word))