python集合相关

集合是一个 无序 、可变、不允许数据重复的容器。集合的元素必须是可哈希的值

set()  #  空集合

1.独有功能

1. 添加元素

   add()
   
   
   
   v1 = {11,22,33,44}
   v1.add(55)
   print(v1) 
   
   
   # {11,22,33,44, 55}
   # {33, 11, 44, 22, 55}
   # 存储原理决定

    

2. 删除

   discard()
   
   
   
   v1 = {11,22,33,44,55}
   v1.discard(55)
   print(v1) 
   
   # {33, 11, 44, 22}

    

3. 交集

   s1 = {"刘能", "赵四", "⽪⻓⼭"}
    s2 = {"刘科⻓", "冯乡⻓", "⽪⻓⼭"}
    ​
    s4 = s1.intersection(s2) # 取两个集合的交集 
    print(s4) # {"⽪⻓⼭"}
    ​
    s3 = s1 & s2              # 取两个集合的交集
    print(s3)

    

4. 并集

   s1 = {"刘能", "赵四", "⽪⻓⼭"}
    s2 = {"刘科⻓", "冯乡⻓", "⽪⻓⼭"}
    s4 = s1.union(s2)       # 取两个集合的并集  {"刘能", "赵四", "⽪⻓⼭","刘科⻓", "冯乡⻓", }
    print(s4)
    s3 = s1 | s2            # 取两个集合的并集
    print(s3)

    

5. 差集

   s1 = {"刘能", "赵四", "⽪⻓⼭"}
    s2 = {"刘科⻓", "冯乡⻓", "⽪⻓⼭"}
    s4 = s1.difference(s2)      # 差集，s1中有且s2中没有的值 {"刘能", "赵四"}
    s6 = s2.difference(s1)      # 差集，s2中有且s1中没有的值 {"刘科⻓", "冯乡⻓"}
    ​
    s3 = s1 - s2               # 差集，s1中有且s2中没有的值
    s5 = s2 - s1               # 差集，s2中有且s1中没有的值
    ​
    print(s5,s6)

2. 公共功能

1. 减，计算差集

   s1 = {11,22,33,44,55}
   s2 = {11,66,33,44,55}
   s3 = s1 - s2 
   s4 = s2 - s1
   print(s3)
   print(s4)
   
   
   # {77, 22}
   # {66, 99}

2. &，计算交集

   s1 = {11,22,33,44,55}
   s2 = {11,66,33,44,55}
   s3 = s1 & s2
   
   print(s3)
   
   
   # {33, 11, 44, 55}

3. |，计算并集

   s1 = {11,22,33,44,55}
   s2 = {11,66,33,44,55}
   s3 = s1 | s2
   print(s3)
   
   
   # {33, 66, 11, 44, 22, 55}

4. 长度

   s1 = {11,22,33,44,55}
   data = len(s1)
   print(data)
   
   # 5

5. for循环

   s1 = {11,22,33,44,55}
   for i in s1:
     print(i)
     
   '''
   33
   11
   44
   22
   55
   '''

 

3.特殊方法

1. update()

   s1 = {11, 22, 33, 44, 55}
    s2 = {11, 111, 33, 44, 55}
    s1.update(s2)
    print(s1)
    ​
    # {33, 11, 44, 111, 22, 55}

    

2. remove()

   s1 = {11, 22, 33, 44, 55}
    s1.remove(11)
    print(s1)
    ​
    # {33, 44, 22, 55}

3. clear()

   s1 = {11, 22, 33, 44, 55}
    print(s1)
    s1.clear()
    print(s1)
    ​
    ​
   # {33, 11, 44, 22, 55}
   # set()

4. pop()

   s1 = {11, 22, 33, 44, 55}
    s1.pop()
    print(s1)
    ​
   # {11, 44, 22, 55}