组合数据类型练习，英文词频统计实例上

Posted 2020-10-08 106洪瑜

1.字典实例：建立学生学号成绩字典，做增删改查遍历操作。

dic={‘055‘:80,‘056‘:81,‘057‘:82,‘058‘:83,‘059‘:84,‘060‘:85,‘061‘:86,‘062‘:87,‘063‘:88,‘064‘:89}
dic[‘065‘]=90   //增
dic.pop(‘055‘)    //删
dic[‘056‘]=91     //改
dic.get(‘070‘,‘不知道‘)   //查
‘070‘ in dic    //查
for i in dic:
    print(i,dic[i])  //遍历

 

2.列表，元组，字典，集合的遍历。

l=list(‘123456123‘)
for i in l:
    print(i)     //列表遍历


t=tuple(‘123456123‘)
for i in t:
    print(i)     //元祖遍历


d={‘055‘:80,‘056‘:81,‘057‘:82}
for i in d:
    print(i,d[i])     //字典遍历


s=set(‘123456123‘)
for i in s:
    print(i)    //集合遍历

 

总结列表，元组，字典，集合的联系与区别。

（1）列表是任意对象的序列。列表用方括号表示。
（2）将一组值打包到一个对象中，称为元组。元组用圆括号表示。元组和列表的大部分操作相同。但是，列表是不固定的，可以随时插入，删除；而元组一旦确认就不能够再更改。所以，系统为了列表的灵活性，就需要牺牲掉一些内存；而元组就更为紧凑。
（3）与列表和元组不同，集合是无序的，也不能通过索引进行访问。此外，集合中的元素不能重复。
（4）字典就是一个关联数组或散列表，其中包含通过关键字索引的对象。用大括号表示。与集合相比，通过关键字索引，所以比集合访问方便。字典是Python解释器中最完善的数据类型。

3.英文词频统计实例

1. 待分析字符串分解提取单词
2. 1. 大小写 txt.lower()
   2. 分隔符‘.,:;?!-_’
   3. 单词列表
3. 单词计数字典

   g=‘‘‘Say something, I‘m giving up on you.
   I‘ll be the one, if you want me to.
   Anywhere, I would‘ve followed you.
   Say something, I‘m giving up on you.
   And I am feeling so small.
   It was over my head
   I know nothing at all.
   And I will stumble and fall.
   I‘m still learning to love
   Just starting to crawl.
   Say something, I‘m giving up on you.
   I‘m sorry that I couldn‘t get to you.
   Anywhere, I would‘ve followed you.
   Say something, I‘m giving up on you.
   And I will swallow my pride.
   You‘re the one that I love
   And I‘m saying goodbye.
   Say something, I‘m giving up on you.
   And I‘m sorry that I couldn‘t get to you.
   And anywhere, I would have followed you.
   Oh-oh-oh-oh say something, I‘m giving up on you.
   Say something, I‘m giving up on you.
   Say something...‘‘‘
   g=g.lower()     // 小写
   for i in ‘,.‘:
       g=g.replace(i,‘ ‘)    //替换
   words=g.split(‘ ‘)       //分隔
   di = {}
   words.sort()
   disc = set(words)
   for i in disc:
       di[i] = 0
   for i in words:
       di[i] = di[i]+1
   items = di.items()
   print(items)