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：
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