List(列表)

列表

序列是Python中最基本的数据结构。序列中的每个元素都分配一个数字 - 它的位置，或索引，第一个索引是0，第二个索引是1，依此类推。

Python有6个序列的内置类型，但最常见的是列表和元组。

序列都可以进行的操作包括索引，切片，加，乘，检查成员。

此外，Python已经内置确定序列的长度以及确定最大和最小的元素的方法。

列表是最常用的Python数据类型，它可以作为一个方括号内的逗号分隔值出现。

列表的数据项不需要具有相同的类型

list1 = [1, 2, 3, 4, 5]
list2 = ['h', 'e', 'll', 'o']
list3 = ['1', 2, '3', 4]

访问列表中的值

使用下标索引来访问列表中的值，同样你也可以使用方括号的形式截取字符。

 

更新列表

你可以对列表的数据项进行修改或更新，你也可以使用append()方法来添加列表项。

 

删除列表元素

可以使用 del 语句来删除列表的的元素。

 

print(list1[0], list1[1])   #访问列表中的元素
print(list1[0:3])           #切片

list1[1] = 100              #更新
list1.append('x')           #增加元素


del list1[0]                #删除
print(list1)

Python列表脚本操作符

列表对 + 和 * 的操作符与字符串相似。+ 号用于组合列表，* 号用于重复列表。

 

a = [1, 2, 3]
b = [4, 5, 6]

print(len(a))   #长度

print(a + b)    #拼接
print(a * 2)    #重复2次
print(3 in a)   #判断a中是否有元素3
for x in a:     #遍历
	print(x)

基本操作：

• 索引
• 切片
• 追加
• 删除
• 长度
• 切片
• 循环
• 包含

 

class list(object):
    """
    list() -> new empty list
    list(iterable) -> new list initialized from iterable's items
    """
    def append(self, p_object): # real signature unknown; restored from __doc__
        """ L.append(object) -- append object to end """
        pass

    def count(self, value): # real signature unknown; restored from __doc__
        """ L.count(value) -> integer -- return number of occurrences of value """
        return 0

    def extend(self, iterable): # real signature unknown; restored from __doc__
        """ L.extend(iterable) -- extend list by appending elements from the iterable """
        pass

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

    def insert(self, index, p_object): # real signature unknown; restored from __doc__
        """ L.insert(index, object) -- insert object before index """
        pass

    def pop(self, index=None): # real signature unknown; restored from __doc__
        """
        L.pop([index]) -> item -- remove and return item at index (default last).
        Raises IndexError if list is empty or index is out of range.
        """
        pass

    def remove(self, value): # real signature unknown; restored from __doc__
        """
        L.remove(value) -- remove first occurrence of value.
        Raises ValueError if the value is not present.
        """
        pass

    def reverse(self): # real signature unknown; restored from __doc__
        """ L.reverse() -- reverse *IN PLACE* """
        pass

    def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__
        """
        L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
        cmp(x, y) -> -1, 0, 1
        """
        pass

    def __add__(self, y): # real signature unknown; restored from __doc__
        """ x.__add__(y) <==> x+y """
        pass

    def __contains__(self, y): # real signature unknown; restored from __doc__
        """ x.__contains__(y) <==> y in x """
        pass

    def __delitem__(self, y): # real signature unknown; restored from __doc__
        """ x.__delitem__(y) <==> del x[y] """
        pass

    def __delslice__(self, i, j): # real signature unknown; restored from __doc__
        """
        x.__delslice__(i, j) <==> del x[i:j]
                   
                   Use of negative indices is not supported.
        """
        pass

    def __eq__(self, y): # real signature unknown; restored from __doc__
        """ x.__eq__(y) <==> x==y """
        pass

    def __getattribute__(self, name): # real signature unknown; restored from __doc__
        """ x.__getattribute__('name') <==> x.name """
        pass

    def __getitem__(self, y): # real signature unknown; restored from __doc__
        """ x.__getitem__(y) <==> x[y] """
        pass

    def __getslice__(self, i, j): # real signature unknown; restored from __doc__
        """
        x.__getslice__(i, j) <==> x[i:j]
                   
                   Use of negative indices is not supported.
        """
        pass

    def __ge__(self, y): # real signature unknown; restored from __doc__
        """ x.__ge__(y) <==> x>=y """
        pass

    def __gt__(self, y): # real signature unknown; restored from __doc__
        """ x.__gt__(y) <==> x>y """
        pass

    def __iadd__(self, y): # real signature unknown; restored from __doc__
        """ x.__iadd__(y) <==> x+=y """
        pass

    def __imul__(self, y): # real signature unknown; restored from __doc__
        """ x.__imul__(y) <==> x*=y """
        pass

    def __init__(self, seq=()): # known special case of list.__init__
        """
        list() -> new empty list
        list(iterable) -> new list initialized from iterable's items
        # (copied from class doc)
        """
        pass

    def __iter__(self): # real signature unknown; restored from __doc__
        """ x.__iter__() <==> iter(x) """
        pass

    def __len__(self): # real signature unknown; restored from __doc__
        """ x.__len__() <==> len(x) """
        pass

    def __le__(self, y): # real signature unknown; restored from __doc__
        """ x.__le__(y) <==> x<=y """
        pass

    def __lt__(self, y): # real signature unknown; restored from __doc__
        """ x.__lt__(y) <==> x<y """
        pass

    def __mul__(self, n): # real signature unknown; restored from __doc__
        """ x.__mul__(n) <==> x*n """
        pass

    @staticmethod # known case of __new__
    def __new__(S, *more): # real signature unknown; restored from __doc__
        """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
        pass

    def __ne__(self, y): # real signature unknown; restored from __doc__
        """ x.__ne__(y) <==> x!=y """
        pass

    def __repr__(self): # real signature unknown; restored from __doc__
        """ x.__repr__() <==> repr(x) """
        pass

    def __reversed__(self): # real signature unknown; restored from __doc__
        """ L.__reversed__() -- return a reverse iterator over the list """
        pass

    def __rmul__(self, n): # real signature unknown; restored from __doc__
        """ x.__rmul__(n) <==> n*x """
        pass

    def __setitem__(self, i, y): # real signature unknown; restored from __doc__
        """ x.__setitem__(i, y) <==> x[i]=y """
        pass

    def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__
        """
        x.__setslice__(i, j, y) <==> x[i:j]=y
                   
                   Use  of negative indices is not supported.
        """
        pass

    def __sizeof__(self): # real signature unknown; restored from __doc__
        """ L.__sizeof__() -- size of L in memory, in bytes """
        pass

    __hash__ = None

list

Python列表函数&方法

Python包含以下函数:

序号	函数
1	len(list) 列表元素个数
2	max(list) 返回列表元素最大值
3	min(list) 返回列表元素最小值
4	list(s 将元组转换为列表

Python包含以下方法:

序号	方法
1	list.append(obj) 在列表末尾添加新的对象
2	list.count(obj) 统计某个元素在列表中出现的次数
3	在列表末尾一次性追加另一个序列中的多个值（用新列表扩展原来的列表）
4	list.index(obj) 从列表中找出某个值第一个匹配项的索引位置
5	list.insert(index, obj) 将对象插入列表
6	list.pop() 移除列表中的一个元素（默认最后一个元素），并且返回该元素的值
7	list.remove(obj) 移除列表中某个值的第一个匹配项
8	list.reverse() 反向列表中元素
9	list.sort(cmp=None, key=None, reverse=False) 对原列表进行排序
10	list.clear() 清空列表
11	list.copy 复制列表