python小白入门4——列表元组

Posted 2021-02-18 huihuangyan

一：列表

#索引

1 li = [‘alex‘,[1,2,3],‘wusir‘,‘egon‘,‘女神‘,‘taibai‘]
2 l1 = li[0]
3 print(l1)
4 l2 = li[1]
5 print(l2)
6 l3 = li[0:3]
7 print(l3)

View Code

#增加 append insert

 1 li.append(‘日天‘)
 2 li.append(1)
 3 print(li)
 4 while 1:
 5     username = input(‘>>>‘)
 6     if username.strip().upper() == ‘Q‘:
 7         break
 8     else:
 9         li.append(username)
10 print(li)
11 li.insert(4,‘春哥‘)
12 print(li)
13 li.extend(‘二哥‘)
14 li.extend([1,2,3])
15 print(li)

View Code

#删

 1 li = [‘taibai‘,‘alex‘,‘wusir‘,‘egon‘,‘女神‘,]
 2 name = li.pop(1)  # 返回值
 3 name = li.pop()  # 默认删除最后一个
 4 print(name,li)
 5 
 6 li.remove(‘taibai‘)  # 按元素去删除
 7 print(li)
 8 
 9 li.clear()  # 清空
10 print(li)
11 
12 del li
13 del li[0:2]  # 切片去删除
14 print(li)

View Code

#改

1 li[0] = ‘男兽‘
2 li[0] = [1,2,3]
3 li[0:3] = ‘云姐plfdslkmgdfjglk‘
4 li[0:3] = [1,2,3,‘春哥‘,‘咸鱼哥‘]
5 print(li)

View Code

#查

1 for i in li:
2     print(i)
3 print(li[0:2])

View Code

#公共方法：

 1 l = len(li)
 2 print(l)
 3 num = li.count(‘taibai‘)
 4 print(num)
 5 print(li.index(‘wusir‘))
 6 li = [1,5,4,7,6,2,3]
 7 
 8 li.sort()      #正向排序
 9 print(li)
10 
11 li.sort(reverse=True)     #反向排序
12 print(li)
13 
14 li.reverse()      #反转    
15 print(li)

View Code

列表转化成字符串  list -----> str    join

1 li = [‘taibai‘,‘alex‘,‘wusir‘,‘egon‘,‘女神‘,]
2 s = ‘++++‘.join(li)

View Code

 

二：元组

#元祖 只读列表，可循环查询，可切片。
#儿子不能改，孙子可能可以改。

 1 tu = (1,2,3,‘alex‘,[2,3,4,‘taibai‘],‘egon‘)
 2   print(tu[3])
 3   print(tu[0:4])
 4   for i in tu:
 5       print(i)
 6 tu[4][3]=tu[4][3].upper()
 7 print(tu)
 8 tu[4].append(‘sb‘)
 9 print(tu)
10 s = ‘alex‘
11 s1 = ‘sb‘.join(s)
12 print(s1)

View Code

 

 

 

 

三：字典

数据类型划分：可变数据类型，不可变数据类型
不可变数据类型：元组，bool int str       可哈希
可变数据类型：list，dict set             不可哈希
dict key 必须是不可变数据类型，可哈希，
    value：任意数据类型。
dict 优点：二分查找去查询
         存储大量的关系型数据
      特点：无序的

 1 dic = {
 2     ‘name‘:[‘大猛‘,‘小孟‘],
 3     ‘py9‘:[{‘num‘:71,‘avg_age‘:18,},
 4            {‘num‘: 71, ‘avg_age‘: 18, },
 5            {‘num‘: 71, ‘avg_age‘: 18, },
 6            ],
 7     True:1,
 8     (1,2,3):‘wuyiyi‘,
 9     2:‘二哥‘,
10 }
11 print(dic)

View Code

#增：

1 dic1 = {‘age‘: 18, ‘name‘: ‘jin‘, ‘sex‘: ‘male‘,}
2 dic1[‘high‘] = 185  #没有键值对，添加
3 dic1[‘age‘] = 16  #如果有键，则值覆盖
4 
5 dic1.setdefault(‘weight‘)  # 有键值对，不做任何改变，没有才添加。
6 dic1.setdefault(‘weight‘,150)
7 dic1.setdefault(‘name‘,‘二哥‘)
8 print(dic1)

View Code

#删

 1 print(dic1.pop(‘age‘))   # 有返回值，按键去删除
 2 print(dic1.pop(‘二哥‘,None))   # 可设置返回值
 3 print(dic1)
 4 
 5 print(dic1.popitem())  # 随机删除 有返回值 元组里面是删除的键值。
 6 print(dic1)
 7 
 8 del dic1[‘name1‘]
 9 print(dic1)
10 del dic1
11 print(dic1)
12 
13 dic1.clear() #清空字典

View Code

#改  update

1 dic1[‘age‘] = 16
2 
3 dic = {"name":"jin","age":18,"sex":"male"}
4 dic2 = {"name":"alex","weight":75}
5 dic2.update(dic)  #
6 
7 print(dic)
8 print(dic2)

View Code

#查

 1 print(dic1.keys(),type(dic1.keys()))
 2 print(dic1.values())
 3 print(dic1.items())
 4 
 5 for i in dic1:
 6     print(i)
 7 for i in dic1.keys():
 8     print(i)
 9 
10 for i in dic1.values():
11     print(i)
12 
13 a,b = 1,2
14 print(a,b)
15 
16 a = 1
17 b = 2
18 a,b = b,a
19 print(a,b)
20 a,b = [1,2],[2,3]
21 a,b = (1,2)
22 print(a,b)
23 
24 for k,v in dic1.items():
25     print(k,v)
26 
27 v1 = dic1[‘name‘]
28 print(v1)
29 
30 v2 = dic1[‘name1‘]  # 报错
31 print(v2)
32 
33 print(dic1.get(‘name1‘,‘没有这个键‘))

View Code

#字典嵌套

 1 dic = {
 2     ‘name‘:[‘alex‘,‘wusir‘,‘taibai‘],
 3     ‘py9‘:{
 4         ‘time‘:‘1213‘,
 5         ‘learn_money‘:19800,
 6         ‘addr‘:‘CBD‘,
 7            },
 8     ‘age‘:21
 9 }
10 dic[‘age‘] = 56
11 print(dic[‘name‘])
12 dic[‘name‘].append(‘ritian‘)
13 l = [1,2,‘wusir‘]
14 l[2] = l[2].upper()
15 dic[‘name‘][1] = dic[‘name‘][1].upper()
16 print(dic)
17 dic[‘py9‘][‘female‘] = 6
18 print(dic)
19 
20 
21 info = input(‘>>>‘).strip()
22 for i in info:
23     if i.isalpha():
24         info = info.replace(i," ")
25 l = info.split()
26 print(len(l))

View Code

 四：集合

集合：可变的数据类型，他里面的元素必须是不可变的数据类型，无序，不重复。

1 set1 = set({1,2,3})
2 set2 = {1,2,3,[2,3],{‘name‘:‘alex‘}}  # 错的
3 print(set1)
4 print(set2)
5 set1 = {‘alex‘,‘wusir‘,‘ritian‘,‘egon‘,‘barry‘,}

View Code

#增

1 #add
2   set1.add(‘女神‘)
3   print(set1)
4 #update
5   set1.update(‘abc‘)
6   print(set1)

View Code

#删除

 1 set1.pop()  # 随机删除
 2 print(set1.pop())  # 有返回值
 3 print(set1)
 4 
 5 set1.remove(‘alex‘)  # 按元素
 6 print(set1)
 7 
 8 } set()
 9 set1.clear()
10 print(set1)  # set()
11 
12 del set1
13 print(set1)

View Code

#查

 1 for i in set1:
 2     print(i)
 3 
 4 set1 = {1,2,3,4,5}
 5 set2 = {4,5,6,7,8}
 6 set3 = set1 & set2
 7 print(set3)  # {4, 5}
 8 print(set1.intersection(set2))  # {4, 5}
 9 
10 set1 = {1,2,3,4,5}
11 set2 = {4,5,6,7,8}
12 print(set1 | set2)  # {1, 2, 3, 4, 5, 6, 7,8}
13 print(set2.union(set1))  # {1, 2, 3, 4, 5, 6, 7}
14 
15 set1 = {1,2,3,4,5}
16 set2 = {4,5,6,7,8}
17 print(set1 ^ set2)  # {1, 2, 3, 6, 7, 8}
18 print(set1.symmetric_difference(set2))  # {1, 2, 3, 6, 7, 8}
19 
20 set1 = {1,2,3,4,5}
21 set2 = {4,5,6,7,8}
22 print(set1 - set2)  # {1, 2, 3}
23 #set1独有的
24 print(set1.difference(set2))  # {1, 2, 3}
25 
26 set1 = {1,2,3,}
27 set2 = {1,2,3,4,5,6}
28 
29 print(set1 < set2)
30 print(set1.issubset(set2))  # 这两个相同，都是说明set1是set2子集。
31 
32 print(set2 > set1)
33 print(set2.issuperset(set1))  # 这两个相同，都是说明set2是set1超集。

View Code

#去重

 1 li = [1,2,33,33,2,1,4,5,6,6]
 2 set1 = set(li)
 3 # print(set1)
 4 li = list(set1)
 5 print(li)
 6 s1 = {1,2,3}
 7 print(s1,type(s1))
 8 
 9 s = frozenset(‘barry‘)
10 print(s,type(s))
11 for i in s:
12     print(i)

View Code