python--元组tuple

元组与列表一样，都是序列。但元组不能修改内容（列表允许）

默认的，元组通过圆括号括起来

1. 使用type函数查看类型

numbers = (1,2,3,4,5,6,7,8,9,0)
print(type(numbers))

2. tuple 函数

tuple 函数的功能与list函数基本一样：以一个序列作为参数并把它转换为元组。

AAA = [1,2,3,4,5]
print (type(AAA))
BBB = tuple(AAA)
print (type(BBB))

元组的基本操作

同其他序列(如：索引，分片，相加，相乘)

1.索引

CCC = (11,22,33,44,55,66,77,88)
print (CCC[0])
print (CCC[4])
print (CCC[-1])

注：使用负数索引，python会从右边开始计算。最后一个元素的位置编号是-1

2.分片

DDDD = (12,222,112,333,44,1234,11111,1,33,455,66667,87787)
print (DDDD[3:6]) # 获取第4个到第6个元素
print (DDDD[-3:]) # 获取最好三个元素
print (DDDD[:3])  # 获取前三个元素

print (DDDD[0:10:2]) # 步长为2分片
print (DDDD[::4])    # 步长为4分片
print (DDDD[::-1])   # 从右到左提取元素

3.序列相加

EE = (2,3,4,5,6)
FF = (11,33,32,88,90)
print (EE+FF)

4.序列相乘

GG = ("I","LOVE","PYTHON","~")
print (GG*5)
HH = (12,23,34,56,78)
print (HH*5)

注：元组的内容不能修改

5.统计元素出现次数count函数

HH = (12,22,33,33,44,44,44,55,12)
print (HH.count(12))
print (HH.count(44))

元组tuple官方文档解析

class tuple(object):
    """
    tuple() -> empty tuple
    tuple(iterable) -> tuple initialized from iterable's items
    
    If the argument is a tuple, the return value is the same object.
    """
    def count(self, value): # real signature unknown; restored from __doc__
        """ T.count(value) -> integer -- return number of occurrences of value """
        return 0

    def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
        """
        T.index(value, [start, [stop]]) -> integer -- return first index of value.
        Raises ValueError if the value is not present.
        """
        return 0

    def __add__(self, *args, **kwargs): # real signature unknown
        """ Return self+value. """
        pass

    def __contains__(self, *args, **kwargs): # real signature unknown
        """ Return key in self. """
        pass

    def __eq__(self, *args, **kwargs): # real signature unknown
        """ Return self==value. """
        pass

    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __getitem__(self, *args, **kwargs): # real signature unknown
        """ Return self[key]. """
        pass

    def __getnewargs__(self, *args, **kwargs): # real signature unknown
        pass

    def __ge__(self, *args, **kwargs): # real signature unknown
        """ Return self>=value. """
        pass

    def __gt__(self, *args, **kwargs): # real signature unknown
        """ Return self>value. """
        pass

    def __hash__(self, *args, **kwargs): # real signature unknown
        """ Return hash(self). """
        pass

    def __init__(self, seq=()): # known special case of tuple.__init__
        """
        tuple() -> empty tuple
        tuple(iterable) -> tuple initialized from iterable's items
        
        If the argument is a tuple, the return value is the same object.
        # (copied from class doc)
        """
        pass

    def __iter__(self, *args, **kwargs): # real signature unknown
        """ Implement iter(self). """
        pass

    def __len__(self, *args, **kwargs): # real signature unknown
        """ Return len(self). """
        pass

    def __le__(self, *args, **kwargs): # real signature unknown
        """ Return self<=value. """
        pass

    def __lt__(self, *args, **kwargs): # real signature unknown
        """ Return self<value. """
        pass

    def __mul__(self, *args, **kwargs): # real signature unknown
        """ Return self*value.n """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __ne__(self, *args, **kwargs): # real signature unknown
        """ Return self!=value. """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    def __rmul__(self, *args, **kwargs): # real signature unknown
        """ Return self*value. """
        pass