数据类型--元祖

浅浅的花香味﹌ 2021-09-30 14:04 301阅读 0赞

### 元祖的概念 ###

元组是另一个数据类型，类似于List（列表）。  
元组用 " ('a',2,'b') " 标识。内部元素用逗号隔开。  
元祖内的元素不能二次赋值，相当于只读列表。  
元祖、列表和字符串都是序列

序列的两个主要特点是：索引操作符&切片操作符  
1、索引操作符让我们可以从序列中抓取一个特定项目。  
2、切片操作符让我们能够获取序列的一个切片，即一部分序列。

1 1、想提取字母b，需要用索引
     2 >>> str1='abcde'
     3 >>> str1[1]
     4 'b'
     5  
     6 2、如果想取值到d，需要用切片
     7 >>> str1[1:4]
     8 'bcd'
     9  
    10 注意：数字是可取的，但是'：'是必须的

### 基本操作： ###

索引  
切片  
循环  
长度  
包含

1 #!/usr/bin/env python
     2 # -*- coding:utf8 -*-
     3 
     4 
     5 tuple = ( 'abcd', 786 , 2.23, 'john', 70.2 )
     6 tinytuple = (123, 'john')
     7 
     8 print(tuple) # 输出完整元组
     9 print(tuple[0]) # 输出元组的第一个元素
    10 print(tuple[1:3]) # 输出第二个至第三个的元素
    11 print(tuple[2:]) # 输出从第三个开始至列表末尾的所有元素
    12 print(tinytuple * 2) # 输出元组两次
    13 print(tuple + tinytuple) # 打印组合的元组
    14 
    15 
    16 返回结果：
    17 ('abcd', 786, 2.23, 'john', 70.2)
    18 abcd
    19 (786, 2.23)
    20 (2.23, 'john', 70.2)
    21 (123, 'john', 123, 'john')
    22 ('abcd', 786, 2.23, 'john', 70.2, 123, 'john')

### 元祖和列表的区别 ###

1 #!/usr/bin/env python
     2 # -*- coding:utf8 -*-
     3 
     4 
     5 tuple = ( 'abcd', 786 , 2.23, 'john', 70.2 )
     6 list = [ 'abcd', 786 , 2.23, 'john', 70.2 ]
     7 
     8 tuple[2] = 1000 # 元组中是非法应用
     9 
    10 输出结果：
    11 tuple[2] = 1000 # 元组中是非法应用
    12 TypeError: 'tuple' object does not support item assignment
    13 
    14 
    15 list[2] = 1000 # 列表中是合法应用
    16 
    17 显示结果：
    18 ['abcd', 786, 1000, 'john', 70.2]

元祖参数：

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

1 lass tuple(object):
      2     """
      3     tuple() -> empty tuple
      4     tuple(iterable) -> tuple initialized from iterable's items
      5     
      6     If the argument is a tuple, the return value is the same object.
      7     """
      8     def count(self, value): # real signature unknown; restored from __doc__
      9         """ T.count(value) -> integer -- return number of occurrences of value """
     10         return 0
     11 
     12     def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
     13         """
     14         T.index(value, [start, [stop]]) -> integer -- return first index of value.
     15         Raises ValueError if the value is not present.
     16         """
     17         return 0
     18 
     19     def __add__(self, y): # real signature unknown; restored from __doc__
     20         """ x.__add__(y) <==> x+y """
     21         pass
     22 
     23     def __contains__(self, y): # real signature unknown; restored from __doc__
     24         """ x.__contains__(y) <==> y in x """
     25         pass
     26 
     27     def __eq__(self, y): # real signature unknown; restored from __doc__
     28         """ x.__eq__(y) <==> x==y """
     29         pass
     30 
     31     def __getattribute__(self, name): # real signature unknown; restored from __doc__
     32         """ x.__getattribute__('name') <==> x.name """
     33         pass
     34 
     35     def __getitem__(self, y): # real signature unknown; restored from __doc__
     36         """ x.__getitem__(y) <==> x[y] """
     37         pass
     38 
     39     def __getnewargs__(self, *args, **kwargs): # real signature unknown
     40         pass
     41 
     42     def __getslice__(self, i, j): # real signature unknown; restored from __doc__
     43         """
     44         x.__getslice__(i, j) <==> x[i:j]
     45                    
     46                    Use of negative indices is not supported.
     47         """
     48         pass
     49 
     50     def __ge__(self, y): # real signature unknown; restored from __doc__
     51         """ x.__ge__(y) <==> x>=y """
     52         pass
     53 
     54     def __gt__(self, y): # real signature unknown; restored from __doc__
     55         """ x.__gt__(y) <==> x>y """
     56         pass
     57 
     58     def __hash__(self): # real signature unknown; restored from __doc__
     59         """ x.__hash__() <==> hash(x) """
     60         pass
     61 
     62     def __init__(self, seq=()): # known special case of tuple.__init__
     63         """
     64         tuple() -> empty tuple
     65         tuple(iterable) -> tuple initialized from iterable's items
     66         
     67         If the argument is a tuple, the return value is the same object.
     68         # (copied from class doc)
     69         """
     70         pass
     71 
     72     def __iter__(self): # real signature unknown; restored from __doc__
     73         """ x.__iter__() <==> iter(x) """
     74         pass
     75 
     76     def __len__(self): # real signature unknown; restored from __doc__
     77         """ x.__len__() <==> len(x) """
     78         pass
     79 
     80     def __le__(self, y): # real signature unknown; restored from __doc__
     81         """ x.__le__(y) <==> x<=y """
     82         pass
     83 
     84     def __lt__(self, y): # real signature unknown; restored from __doc__
     85         """ x.__lt__(y) <==> x<y """
     86         pass
     87 
     88     def __mul__(self, n): # real signature unknown; restored from __doc__
     89         """ x.__mul__(n) <==> x*n """
     90         pass
     91 
     92     @staticmethod # known case of __new__
     93     def __new__(S, *more): # real signature unknown; restored from __doc__
     94         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
     95         pass
     96 
     97     def __ne__(self, y): # real signature unknown; restored from __doc__
     98         """ x.__ne__(y) <==> x!=y """
     99         pass
    100 
    101     def __repr__(self): # real signature unknown; restored from __doc__
    102         """ x.__repr__() <==> repr(x) """
    103         pass
    104 
    105     def __rmul__(self, n): # real signature unknown; restored from __doc__
    106         """ x.__rmul__(n) <==> n*x """
    107         pass
    108 
    109     def __sizeof__(self): # real signature unknown; restored from __doc__
    110         """ T.__sizeof__() -- size of T in memory, in bytes """
    111         pass
    112 
    113 tuple

元祖源代码

转载于:https://www.cnblogs.com/abobo/p/8032731.html

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