Python 的基本資料型態(二)

群集型態：

• Python 支援多種資料結構，包含清單(list)、集合(set)、字典(dict)、Tuple ！
• 每一種資料結構有其使用方式，請注意其不同的使用條件！

清單(list)：

1. 清單(list)：其使用特性為有序、具備索引值、內容長度可變動，使用 [] 符號，內容使用逗號區隔！
   • 範例 1：

     #python3
     Python 3.8.3 (default, Aug 31 2020, 16:03:14) 
     [GCC 8.3.1 20191121 (Red Hat 8.3.1-5)] on linux
     Type "help", "copyright", "credits" or "license" for more information.
     >>> names = ['Peter', 'James', 'Mary']
     >>> names
     ['Peter', 'James', 'Mary']
     >>> print(names)
     ['Peter', 'James', 'Mary']
     >>> print(names[0])
     Peter
     

2. 可使用 append()、extend()、pop()、remove()、reverse()、sort() 等方法，進行資料結構的調整！
   • 範例 2：

     >>> names = ['Peter', 'James', 'Mary']
     >>> names
     ['Peter', 'James', 'Mary', 'D', 'a', 'v', 'i', 'd']
     >>> names.remove('D')
     >>> names
     ['Peter', 'James', 'Mary', 'a', 'v', 'i', 'd']
     >>> names.remove(names[3])
     >>> names
     ['Peter', 'James', 'Mary', 'v', 'i', 'd']
     >>> names.remove(names[3-4])
     >>> names
     ['Peter', 'James', 'Mary', 'v', 'i']
      (註：因為 3-4 = -1，所以是由後往前數一個欄位)
     >>> names.pop(1)
     'James'
     >>> names
     ['Peter', 'Mary', 'v', 'i']
     (註：pop() 是指要提出哪一個欄位的值！提出後，不寫回原欄位！)
     >>> names.sort()
     >>> names
     ['Mary', 'Peter', 'i', 'v']
     >>> names.append('James')
     >>> names
     ['Mary', 'Peter', 'i', 'v', 'James']
     >>> names.reverse()
     >>> names
     ['James', 'v', 'i', 'Peter', 'Mary']
     >>> names.extend(['David','Poll'])
     >>> names
     ['James', 'v', 'i', 'Peter', 'Mary', 'David', 'Poll']
     

集合(set)：

1. 集合(set)：其特色為內容是無序但不重複！使用{}符號包含元素，元素間使用逗號分隔！
   • 範例 1：

     ＃python3
     Python 3.8.3 (default, Aug 31 2020, 16:03:14) 
     [GCC 8.3.1 20191121 (Red Hat 8.3.1-5)] on linux
     Type "help", "copyright", "credits" or "license" for more information.
     >>>
     >>> names = set()
     >>> names
     set()
     >>> names.add('Peter')
     >>> names
     {'Peter'}
     >>> names = {'Peter','Mary'}
     >>> names
     {'Mary', 'Peter'}
     (註：集合會自動排序)
     >>> names.add('Peter')
     >>> names
     {'Mary', 'Peter'}
     >>> names.remove('Peter')
     >>> names
     {'Mary'}
     >>> 'Peter' in names
     False
     

字典(dict)：

1. 字典(dict)：成雙成對的 key-value 架構！
   • 範例 1：

     ＃python3
     Python 3.8.3 (default, Aug 31 2020, 16:03:14) 
     [GCC 8.3.1 20191121 (Red Hat 8.3.1-5)] on linux
     Type "help", "copyright", "credits" or "license" for more information.
     >>>
     >>> userpws = {'Peter':32123 , 'David':'abc123'}
     >>> userpws['David']
     'abc123'
     >>> userpws['Peter']
     32123
     >>> userpws['Mary'] = 987654
     >>> userpws
     {'Peter': 32123, 'David': 'abc123', 'Mary': 987654}
     >>> del userpws['David']
     >>> userpws
     {'Peter': 32123, 'Mary': 987654}
     >>> 'Mary' in userpws
     True
     >>> userpws['Mary'] = 12345
     >>> userpws
     {'Peter': 32123, 'Mary': 12345}
     >>> userpws.get('David')
     >>> userpws.get('David')  == None
     True
     >>> userpws.get('David', 'ABC123')
     'ABC123'
     >>> userpws
     {'Peter': 32123, 'Mary': 12345}
     (註：get 只是暫存資料！)
     >>> list(userpws.items())
     [('Peter', 32123), ('Mary', 12345)]
     >>> list(userpws.keys())
     ['Peter', 'Mary']
     >>> list(userpws.values())
     [32123, 12345]
     
     

Tuple(tuple)：

1. Tuple(tuple)：有序的資料結構，使用[]指定索引元素！建立之後，就無法變動！
   • 範例 1：

     ＃python3
     Python 3.8.3 (default, Aug 31 2020, 16:03:14) 
     [GCC 8.3.1 20191121 (Red Hat 8.3.1-5)] on linux
     Type "help", "copyright", "credits" or "license" for more information.
     >>>
     >>> 10,
     (10,)
     >>> 10,20,30
     (10, 20, 30)
     >>> acct = 1, 'Peter', True
     >>> acct
     (1, 'Peter', True)
     >>> type(acct)
     <class 'tuple'>
     >>> print(acct[1])
     Peter
     >>> acct[1] = "Mary"
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: 'tuple' object does not support item assignment
     >>> id, names, access = acct
     >>> names
     'Peter'
     >>> access, names, id = id, names, access
     >>> access
     1
     (註：用來置換變數值內容)
     >>> a, *b, c = [1,2,3,4,5]
     >>> b
     [2, 3, 4]