1.列表：由字符串創建一個作業評分列表，做增刪改查詢統計遍歷操作。例如，查詢第一個3分的下標，統計1分的同學有多少個，3分的同學有多少個等。
1 >>> ls = list('132231321132') 2 >>> ls 3 ['1', '3', '2', '2', '3', '1', '3', '2', '1', '1', '3', '2'] 4 >>> ll=['123456'] 5 >>> ll 6 ['123456'] 7 #增 8 >>> ls.append(9) 9 >>> ls 10 ['1', '3', '2', '2', '3', '1', '3', '2', '1', '1', '3', '2', 9] 11 #改 12 >>> ls.insert(0,'10') 13 >>> ls 14 ['10', '1', '3', '2', '2', '3', '1', '3', '2', '1', '1', '3', '2', 9] 15 #刪 16 >>> ls.pop(0) 17 '10' 18 >>> ls 19 ['1', '3', '2', '2', '3', '1', '3', '2', '1', '1', '3', '2', 9] 20 #查 21 >>> ls.index('3') 22 1 23 #統計 24 >>> ls.count('1') 25 4 26 >>> ls.count('3') 27 4 28 >>>
2.字典：建立學生學號成績字典，做增刪改查遍歷操作。
1 #list()+zip()建立字典 2 >>> dic=dict(zip([1,2,3],['98','100','88'])) 3 >>> dic 4 {1: '98', 2: '100', 3: '88'} 5 6 #增update() 7 >>> dic2={4:'95'} 8 >>> dic.update(dic2) 9 >>> dic 10 {1: '98', 2: '100', 3: '88', 4: '95'} 11 12 #刪pop()/del a[k] 13 >>> dic.pop(2) 14 '100' 15 >>> dic 16 {1: '98', 3: '88', 4: '95'} 17 #del 18 >>> dic 19 {1: '120', 3: '88', 4: '95'} 20 >>> del dic[3] 21 >>> dic 22 {1: '120', 4: '95'} 23 24 #改insert() 25 >>> dic[1]='120' 26 >>> dic 27 {1: '120', 3: '88', 4: '95'} 28 29 #查get() 30 >>> dic 31 {1: '98', 3: '88', 4: '95'} 32 >>> dic.get(4) 33 '95' 34 >>> dic.get(5,'沒有') 35 '沒有' 36 #直接查也可以 37 >>> dic[4] 38 '95' 39 40 # 返回一個list：keys()/values()/items() 41 >>> dic.keys() 42 dict_keys([1, 3, 4]) 43 >>> dic.values() 44 dict_values(['98', '88', '95']) 45 46 #將dict中的元素變為元祖items() 47 >>> dic.items() 48 dict_items([(1, '98'), (3, '88'), (4, '95')])
3.列表，元組，字典，集合的遍歷。
1 #list 2 ls=list('654561') 3 #set 4 st={'100','100','98','95','96','96'} 5 #tuple 6 tup='a','b',1,st 7 #('a', 'b', 1, {'98', '96', '100', '95'}) 8 #dict 9 dic={'a':'blue','b':'red','c':'white'} 10 11 print('遍歷list'.center(50,'=')) 12 for i in ls: 13 print(i,end=' ') 14 print('\n') 15 print('遍歷set'.center(50,'=')) 16 for i in st: 17 print(i,end=' ') 18 print('\n') 19 print('遍歷tuple'.center(50,'=')) 20 for i in tup: 21 print(i,end=' ') 22 print('\n') 23 print('遍歷dict'.center(50,'=')) 24 for (k,v) in dic.items(): 25 print('dict[%s]='%k,v)
4.總結列表，元組，字典，集合的聯系與區別。
| 屬性 | 列表list | 元祖tuple | 字典dict | 集合set |
| 有序 | 是 （正向遞增/反向遞減） | 是 | 無 | 無 |
| 數據可重復 | 是 | 是 | key值唯一 | 否 |
| 數據可修改 | 是 | 否 | 是 | 是 |
| 特點 | 查詢速度隨內容增加而變慢 占用內存較小 |
表達固定數據項、函數多返回值、 多變量同步賦值、循環遍歷等情況下適用 |
改&查操作速度快， 不會因key值增加而變慢。 占用內存大，內存浪費多 （利用空間成本換時間） |
數據獨立性： 能夠過濾重復參數 |
5.英文詞頻統計實例：待分析字符串，分解提取單詞，大小寫 txt.lower()，分隔符'.,:;?!-_’，計數字典，排序list.sort()，輸出TOP(10)
1 #待分析字符串，分解提取單詞，大小寫 txt.lower()，分隔符'.,:;?!-_’，計數字典，排序list.sort()，輸出TOP(10) 2 song=''' 3 Oh woah 4 Oh woah 5 Oh woahohhohh 6 7 You know you love me, I know you care 8 You shout whenever, and I'll be there 9 You want my love, you want my heart 10 And we will never ever ever be apart 11 Are we an item? Girl quit playing 12 We're just friends, what are you saying 13 Said there's another and look right in my eyes 14 My first love broke my heart for the first time 15 And I was like 16 17 Baby, baby, baby, oh like 18 Baby, baby, baby, no like 19 Baby, baby, baby, oh 20 I thought you'd always been mine, mine 21 Baby, baby, baby, oh like 22 Baby, baby, baby, no like 23 Baby, baby, baby, oh 24 I thought you'd always been mine, mine 25 Oh, Oh 26 27 For you, I would have done whatever 28 And I just can't believe we ain't together 29 And I wanna play it cool, but I'm losing you 30 I'll buy you anything, I'll buy you any ring 31 And I'm in pieces, baby fix me 32 And you'll shake me till you wake me from this bad dream 33 I'm going down, down, down, down 34 And I just can't believe my first love won't be around 35 And I'm now like 36 37 Baby, baby, baby, oh like 38 Baby, baby, baby, no like 39 Baby, baby, baby, oh 40 I thought you'd always been mine, mine 41 Baby, baby, baby, oh like 42 Baby, baby, baby, no like 43 Baby, baby, baby, oh 44 I thought you'd always been mine, mine 45 46 When I was 13 I had my first love 47 There was nobody that compared to my baby 48 And nobody came between us or could ever come above 49 She had me going crazy 50 Oh I was starstruck 51 She woke me up daily don't need no starbucks 52 She made my heart pound 53 Asking for a beat when I see her in the street 54 And at school on the playground 55 But I really wanna see her on the weekend 56 She knows she got me dazy 57 Cause she was so amazing 58 And now my heart is breaking 59 But I'll just keep on saying 60 61 Baby, baby, baby, oh like 62 Baby, baby, baby, no like 63 Baby, baby, baby, oh 64 I thought you'd always been mine, mine 65 Baby, baby, baby, oh like 66 Baby, baby, baby, no like 67 Baby, baby, baby, oh 68 I thought you'd always been mine, mine 69 Now I'm all gone 70 Now I'm all gone 71 Now I'm all gone 72 Now I'm all gone 73 I am gone 74 75 ''' 76 #1.全文轉為小寫 77 song=song.lower() 78 79 #2.去除標點符號 80 for i in ',.?!\n': 81 song=song.replace(i,' ') 82 83 #3.分解提取單詞 84 words=song.split(' ')#將字符串以' '為依據划分為一個個單詞 85 86 #expend={'in','and','so','i','ll','is','her','are','a','an'} 87 #for i in expend: 88 # songs=words.replace(i,'*') 89 90 #4.做一個空字典計數 91 dic={} 92 keys=set(words)#用數組的獨立性取出字典的key值 93 for i in keys: 94 dic[i]=words.count(i)#dic[i]輸出key值 95 96 #5.排序 97 tupleee=list(dic.items()) 98 tupleee.sort(key=lambda x:x[1],reverse=True) 99 100 #6.輸出TOP(10) 101 for i in range(10): 102 print(tupleee[i])
