1.列表实例：由字符串创建一个作业评分列表，做增删改查询统计遍历操作。例如，查询第一个3分的下标，统计1分的同学有多少个，3分的同学有多少个等。
>>> ls=list('1231323232323131323') >>> ls ['1', '2', '3', '1', '3', '2', '3', '2', '3', '2', '3', '2', '3', '1', '3', '1', '3', '2', '3'] >>> ls.append('4') >>> ls.append('5') >>> ls ['1', '2', '3', '1', '3', '2', '3', '2', '3', '2', '3', '2', '3', '1', '3', '1', '3', '2', '3', '4', '5'] >>> ls.pop() '5' >>> ls ['1', '2', '3', '1', '3', '2', '3', '2', '3', '2', '3', '2', '3', '1', '3', '1', '3', '2', '3', '4'] >>> ls.index('3') 2 >>> ls.count('1') 4 >>> ls.count('3') 9 >>>
2.字典实例：建立学生学号成绩字典，做增删改查遍历操作。
>>> d={'01':'95','02':'85','03':'90','04':'92','05':'72','06':'93'}
>>> d.keys()
dict_keys(['01', '02', '03', '04', '05', '06'])
>>> d.values()
dict_values(['95', '85', '90', '92', '72', '93'])
>>> d.get('03','100')
'90'
>>> d['99']='99'
>>> d
{'01': '95', '02': '85', '03': '90', '04': '92', '05': '72', '06': '93', '99': '99'}
3.列表，元组，字典，集合的遍历。总结列表，元组，字典，集合的联系与区别。
>>> l=list('123456665432145') >>> t=tuple('65432566123333') >>> d={'01':'刘','02':'张','03':'王','04':'李'} >>> s=set('123654598777296582') >>> l ['1', '2', '3', '4', '5', '6', '6', '6', '5', '4', '3', '2', '1', '4', '5'] >>> >>> t ('6', '5', '4', '3', '2', '5', '6', '6', '1', '2', '3', '3', '3', '3') >>> >>> d {'01': '刘', '02': '张', '03': '王', '04': '李'} >>> >>> s {'8', '2', '7', '9', '1', '3', '6', '5', '4'} >>>
列表使用方括号，元组使用小括号，字典使用花括号，集合使用[()]；
元组创建很简单，只需要在括号中添加元素，并使用逗号隔开即可，列表则复杂多；
列表、字典、集合能增加、修改、删除，元组不能；
4.英文词频统计实例
new = '''An empty street An empty house A hole inside heart all alone and the rooms Are getting smaller I wonder how I wonder why I wonder where they are The days we had The songs we sang together And oh! my love holding on forever Reaching for a love That seems so far So I say a litter prayer No my dream will take me there Where the skies are blue to see you once again my love Overseas from coast to coast Find a place I love the most Where the fields are green To see you once again My love I Try to read I go to work laughing with my friends But I can't stop to keep myself From thinking I wonder how I wonder why I wonder where they are The days we had The songs we sang togetther And oh! my love I'mholding on forever Reaching for a love That seems so far So I say a litter prayer No my dream will take me there Where the skies are blue to see you once again my love Overseas from coast to coast Find a place I love the most Where the fields are green To see you once again To hold you in my arms To promise my love To tell you from my heart You are all I'm thinking of Reaching for a love That seems so far So I say a litter prayer No my dream will take me there Where the skies are blue to see you once again my love Overseas from coast to coast Find a place I love the most Where the fields are green To see you once again My love And hope my dream will take me there Where the skies are blue to see you once again my love Overseas from coast to coast Find a place I love the most Where the fields are green To see you once again My love''' new=new.lower() for i in '.,"': new=new.replace(i,' ') word = new.split(' ') dic ={} keys = set(word) for i in keys: dic[i]=word.count(i) words = list(dic.items()) words.sort(key= lambda x:x[1],reverse = True) for i in range(10): print(word[i])
