Python – Set 資料型態物件

測試環境為 CentOS 8 x86_64 (虛擬機)

參考文章 – https://docs.python.org/zh-tw/3/tutorial/datastructures.html#sets

集合 (Sets) 存儲一組無序且不重複的元素,支援 and 聯集 , or 交集 , not 差集和 xor 互斥等數學運算.

其他資料型態

1. String – https://benjr.tw/104605
   使用單,雙 或是 三重引號來表示為字串.
2. List – https://benjr.tw/104232
   使用 中括弧 [ ] 表示 ,其中資料用逗號做區隔.
3. dic – https://benjr.tw/104234
   使用 大括弧 { } 表示 ,格式為 key:valu ( pair 組成 並由逗點隔開).
4. Tuple – https://benjr.tw/104461
   使用 小括號 ( ) 表示 ,其中資料用逗號做區隔.
5. set – https://benjr.tw/104696
   大括弧 { } 表示 ,其中資料用逗號做區隔.

[root@localhost ~]# python3
Python 3.6.8 (default, Mar 25 2022, 11:15:52)
[GCC 8.5.0 20210514 (Red Hat 8.5.0-10)] on linux
Type "help", "copyright", "credits" or "license" for more information.

• 範例 : 集合 (Sets)無序且不重複的元素

  >>> s1={1,1,2,3,4}
  >>> s1
  {1, 2, 3, 4}
  

• 範例 : and 聯集 , or 交集 , not 差集和 xor 互斥等數學運算.

  >>> s1={1,2,3,4}
  >>> s1
  {1, 2, 3, 4}
  >>> s2={4,5,6,7}
  >>> s2
  {4, 5, 6, 7}
  

  not 差集

  >>> s1-s2
  {1, 2, 3}
  

  and 聯集

  >>> s1&s2
  {4}
  

  or 交集

  >>> s1|s2
  {1, 2, 3, 4, 5, 6, 7}
  

  s1 與 s2

  xor 互斥 (xor 為相同為 0 ,不同為 1 , 只會顯示 1 (不同的))

  >>> s1^s2
  {1, 2, 3, 5, 6, 7}
  
  

• 範例 : 使用 set 建立 Set 資料型態物件
  需使用 小括弧 () .

  >>> a = set('abracadabra')
  >>> a
  {'b', 'd', 'a', 'r', 'c'}
  

• 範例 : set comprehensions (集合綜合運算)

  >>> a = {x for x in 'abracadabra' if x not in 'abc'}
  >>> a
  {'d', 'r'}
  

set 的 Method – https://www.w3schools.com/python/python_ref_set.asp

• add()
  Adds an element to the set
• clear()
  Removes all the elements from the set
• copy()
  Returns a copy of the set
• difference()
  Returns a set containing the difference between two or more sets
• difference_update()
  Removes the items in this set that are also included in another, specified set
• discard()
  Remove the specified item
• intersection()
  Returns a set, that is the intersection of two or more sets
• intersection_update()
  Removes the items in this set that are not present in other, specified set(s)
• isdisjoint()
  Returns whether two sets have a intersection or not
• issubset()
  Returns whether another set contains this set or not
• issuperset()
  Returns whether this set contains another set or not
• pop()
  Removes an element from the set
• remove()
  Removes the specified element
• symmetric_difference()
  Returns a set with the symmetric differences of two sets
• symmetric_difference_update()
  inserts the symmetric differences from this set and another
• union()
  Return a set containing the union of sets
• update()
  Update the set with another set, or any other iterable