- 字典实例：建立学生学号成绩字典，做增删改查遍历操作。
dic={}
dic['01']='99'
dic['02']='84'
dic['03']='79'
print('学生学号成绩字典：',dic)
dic['04']='75'
print('增加：',dic)
dic.pop('04')
print('删除：',dic)
dic['01']='94'
print('修改：',dic)
for i in dic:
print('遍历：',i,dic[i]) - 列表，元组，字典，集合的遍历。
list=['23143795']
print('列表：',list)
for i in list:
print('列表的遍历：',i)
t=('23143795')
print('元组：',t)
for i in t:
print('元组的遍历：',i)
s=['75','69','90']
n=['a','b','c']
ns=dict(zip(n,s))
print('字典：',ns)
for i in ns:
print('字典的遍历：',i,ns[i])
h=set([1,2,3])
print('集合：',h)
for i in h:
print('集合的遍历：',i)
总结列表，元组，字典，集合的联系与区别。
列表可重复，类型可不同，用“[]”表示；
元组元组是只读的，不能修改，元组用“()”表示；
字典存储键值对数据，字典最外面用大括号，每一组用冒号连接；
集合集合最好的应用是去重，通过一个set函数转换成集合。
3.英文词频统计实例待分析字符串分解提取单词
- 大小写 txt.lower()
- 分隔符'.,:;?!-_’
- 单词列表
- 单词计数字典
s='''It's been a long day, without you my friend
And I'll tell you all about it when I see you again
We've come a long way from where we began
Oh I'll tell you all about it when I see you again
When I see you again
Damn who knew all the planes we flew
Good things we've been through
That I'll be standing right here
Talking to you about another path
I know we loved to hit the road and laugh
But something told me that it wouldn't last
Had to switch up look at things different see the bigger picture
Those were the days hard work forever pays
Now I see you in a better place
How could we not talk about family when family's all that we got?
Everything I went through you were standing there by my side
And now you gonna be with me for the last ride
It's been a long day without you my friend
And I'll tell you all about it when I see you again
We've come a long way from where we began
Oh I'll tell you all about it when I see you again
When I see you again
'''
s=s.lower()
print('转化为小写：',s)
for i in ',.':
s=s.replace(i,' ')
print('替换符号：',s)
b=s.split(' ')
print('分隔出一个一个的单词:',b)
print('when出现的次数:',b.count('when'))
print('my出现的次数:',b.count('my'))