내장 데이터 구조 - 집합

  
     
In [1]: s = set()

set()             
In [3]: s = set([1,2,3])
In [4]: s
Out[4]: {1, 2, 3}

{}               ，          
In [2]: s = {1,2,3,4,3,4}
In [3]: s
Out[3]: {1, 2, 3, 4}

  
add()         None，           
In [4]: s.add('a')
In [5]: s
Out[5]: {'a', 1, 2, 3, 4}
In [6]: s.add(1)
In [7]: 

update()      ，         
In [7]: s.update({'x','y'})
In [8]: s
Out[8]: {1, 2, 3, 4, 'x', 'a', 'y'}

    hash，              
In [19]: s.add([1,2,3])
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
 in ()
----> 1 s.add([1,2,3])

TypeError: unhashable type: 'list'

  

remove()        
In [20]: s
Out[20]: {1, 2, 3, 4, 7, 'x', 'a', 8, 'y'}
In [21]: s.remove(1)
In [22]: s
Out[22]: {2, 3, 4, 7, 'x', 'a', 8, 'y'}

        ，  
In [23]: s.remove(1)
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
 in ()
----> 1 s.remove(1)

KeyError: 1

discard()        ，       
In [24]: s
Out[24]: {2, 3, 4, 7, 'x', 'a', 8, 'y'}

In [25]: s.discard(2)

In [26]: s
Out[26]: {3, 4, 7, 'x', 'a', 8, 'y'}

In [27]: s.discard(2)


pop()           ，       ,        
In [28]: s
Out[28]: {3, 4, 7, 'x', 'a', 8, 'y'}

In [29]: s.pop()
Out[29]: 3
In [37]: s
Out[37]: set()

In [38]: s.pop()
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
 in ()
----> 1 s.pop()

KeyError: 'pop from an empty set'


     
        ，            ，        

    

In [41]: a = {1,2,3,4,5,6,7,8}
In [42]: b = {3,4,5,6,'a', 'b'}

  
In [43]: a.union(b)
Out[43]: {1, 2, 3, 4, 5, 6, 7, 8, 'a', 'b'}
  
In [44]: a.intersection(b)
Out[44]: {3, 4, 5, 6}
  
In [45]: a.difference(b)
Out[45]: {1, 2, 7, 8}
    ，         
In [46]: a.symmetric_difference(b)
Out[46]: {1, 2, 7, 'a', 8, 'b'}

     ，     - ，&, |，^ ,  +
In [47]: a&b
Out[47]: {3, 4, 5, 6}

In [48]: a|b
Out[48]: {1, 2, 3, 4, 5, 6, 7, 8, 'a', 'b'}

In [49]: a - b
Out[49]: {1, 2, 7, 8}


intersection_update()       ，    None
In [50]: a
Out[50]: {1, 2, 3, 4, 5, 6, 7, 8}

In [51]: b
Out[51]: {3, 4, 5, 6, 'a', 'b'}

In [52]: a.intersection_update(b)

In [53]: a
Out[53]: {3, 4, 5, 6}

In [54]: b
Out[54]: {3, 4, 5, 6, 'a', 'b'}


  ，  
In [1]: a = {1,2,3,4,5,6,7}

In [2]: b = {3,4}

In [3]: a.issuperset(b)
Out[3]: True

In [4]: b.issubset(a)
Out[4]: True

isdisjoint()           ，    True，   Flase
In [5]: a.isdisjoint(b)
Out[5]: False

In [6]: a.isdisjoint({8,9})
Out[6]: True