组合数据类型，英文词频统计

1.总结列表，元组，字典，集合的联系与区别：

列表：list [, ,]   list是一种有序的序列，可以随时添加和删除元素，元素类型可以不同。

元组： tuple['' ,'' ]元组一旦创建，便不能修改,只能做读取操作。

字典：dict {key:value,}  dict的key 不能重复，必须是不可变对象。

集合：set {,,}  也是一组key的集合，key不能重复。

 

2.列表，元组，字典，集合的遍历。

列表：

li=list('abcde')
print(li)
for lis in li:
    print(lis)

运行结果：

元组：

classmates=["Michale","Bob","Tracy","李三","Tracy",56]
print(classmates)
for tuple in classmates:
    print(tuple)

运行结果：

字典：

classmates={"Bob":75,"Michael":95,"Tracy":85}
print(classmates)
for dic in classmates:
    print(dic)

运行结果：

集合：

s={1,2,3,4,4,6}
print(s)
for set in s:
    print(set)

运行结果：

 

英文词频统计：

str='The steps that we left behind' \
    '　Your lonely eyes stare back at mine' \
    '　In pictures from that time'\
    '　I hold my heart,closing my eyes'\
    '　I see your smile,lies behind'\
    '　In this place,you entered my life'\
    '　How I wish,you were still mine'\
    '　I know that if I see you again'\
    '　Beside that cafe we met'\
    '　I＇d forget about the past'\
    '　Lose track of time,with you'\
    '　Talking about our lives'\
    '　To show you a whole new side of me'\
    '　And see the changes we＇ve made,can we'\
    '　Be more than we have been'\
    '　Start our story again'\
    '　All I can say,is tell you just one thing'\
    '　好久不见'\
    '　I hold my heart,closing my eyes'\
    '　I see your smile,lies behind'\
    '　In this place,you entered my life'\
    '　How I wish,you were still mine'\
    '　I know that if I see you again'\
    '　Beside that cafe we met'\
    '　I＇d forget about the past'\
    '　Lose track of time,with you'\
    '　Talking about our lives'\
    '　To show you a whole new side of me'\
    '　And see the changes we＇ve made,can we'\
    '　Be more than we have been'\
    '　Start our story again'\
    '　All I can say,is tell you just one thing'\
    '　好久不见'
print(str.lower())
print(str.count("you"))

list=str.split()
print(list)
for song in list:
    print(song,list.count(song))

运行结果：