自学Python2.2-基本数据类型-列表list(object)

Python List方法总结 

一、 列表简介：

   列表是序列对象，可包含任意的Python数据信息，如字符串、数字、列表、元组等
   列表的数据是可变的，我们可通过对象方法对列表中的数据进行增加、修改、删除等操作
   可以通过list(seq)函数把一个序列类型转换成一个列表

运算符： 索引运算[i] ,切片运算[i:j]， 扩展切片运算[i:j:stride]

支持运算：索引，切片，min(),max(),len()等

1. 列表赋值：

l1=[] 空列表   #但是内存有位置存放，使用id(l1)查看，输出45623200 

l2=[1,2,3,4,5,6,] 

l3=[1,'b']

l4=[[1,2],['a','b']]  嵌套列表

2.列表操作

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l2=[1,2,3,4,5,6,] l2[3]=78 print(l2)

 输出[1, 2, 3, 78, 5, 6]

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l2=[1,2,3,4,5,6,] l2[4]='xyz' print(l2)

输出[1, 2, 3, 4, 'xyz', 6]

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l2=[1,2,3,4,5,6,] result=l2[1:3] #表示分片偏移，第一个数值表示提取的第一个元素编号，包含在分片内；第二个数值表示分片后剩余的的第一个元素编号，不包含在分片内 print(result)

输出[2, 3]

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l2=[1,2,3,4,5,6,] l2[1:3]=[] #表示删除， 也可以使用del([l2[1:3]]) print(l2)

输出[1, 4, 5, 6]

二、列表的方法

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) -> None -- append object to end """
        pass

    def clear(self): # real signature unknown; restored from __doc__
        """ L.clear() -> None -- remove all items from L """
        pass

    def copy(self): # real signature unknown; restored from __doc__
        """ L.copy() -> list -- a shallow copy of L """
        return []

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

    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 __delitem__(self, *args, **kwargs): # real signature unknown
        """ Delete self[key]. """
        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, y): # real signature unknown; restored from __doc__
        """ x.__getitem__(y) <==> x[y] """
        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 __iadd__(self, *args, **kwargs): # real signature unknown
        """ Implement self+=value. """
        pass

    def __imul__(self, *args, **kwargs): # real signature unknown
        """ Implement self*=value. """
        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, *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 __reversed__(self): # real signature unknown; restored from __doc__
        """ L.__reversed__() -- return a reverse iterator over the list """
        pass

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

    def __setitem__(self, *args, **kwargs): # real signature unknown
        """ Set self[key] to value. """
        pass

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

    __hash__ = None

1．append(self, p_object)，在列表尾部追加单个对象x，使用多个参数会引起异常

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1 2 3

list=[1,2,3,4,5,] list.append(88) print(list)

输出[1, 2, 3, 4, 5, 88]　　

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1 2 3 4

l1=[1,2,3,4,5,] l2=['carlos',77,] l1.append(l2) print(l1)

输出[1, 2, 3, 4, 5, ['carlos', 77]]

2. clear(self) 

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l1=[1,2,3,4,5,] l1.clear() print(l1)

输出[]　

3. copy(self)

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l1=[1,2,3,4,5,] l2=l1.copy() print(l1) print(l2)

输出

[1, 2, 3, 4, 5]
[1, 2, 3, 4, 5]

4. count(self, value)，返回对象value在列表中出现的次数

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l1=['to',2,'be','to',5,] result=l1.count('to') print(result)

输出2

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l1=[[1,2],'alex','be','to',[1,2],[2],[1,2],] result=l1.count([1,2]) print(result)

输出3

5.  extend(self, iterable)，将列表中的表项添加到列表中，返回None

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1 2 3 4 5 6

l1=[1,2,3,4,5,6,] print(id(l1)) l2=['carlos',99,[3,7],] l3=l1.extend(l2,) print(l1)   #extend修改被扩展序列 print(id(l1))

输出

33039344
[1, 2, 3, 4, 5, 6, 'carlos', 99, [3, 7]]
33039344

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1 2 3 4 5 6

l1=[1,2,3,4,5,6,] print(id(l1)) l2=['carlos',99,[3,7],] l3=l1+l2 print(l3)   # 原始连接的操作是返回一个全新的列表 print(id(l3))

输出　　

38806512
[1, 2, 3, 4, 5, 6, 'carlos', 99, [3, 7]]
38807592

6. index(self, value, start=None, stop=None)，返回列表中匹配对象value的第一个列表项的索引，无匹配元素时产生异常

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1 2 3

l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,] l2=l1.index(5) print(l2)   # 返回列表中匹配对象value的第一个列表项的索引

输出4

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,] l2=l1.index(5,5,10) print(l2)   # 返回列表中匹配对象value的索引5,10 之前匹配的项

输出9　　

7.insert(self, index, p_object)，在索引为i的元素前插入对象x，如list.insert(0,x)在第一项前插入对象，返回None

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,] l1.insert(3,'alex') print(l1)

输出[1, 2, 3, 'alex', 4, 5, 6, 'carlos', 99, [3, 7], 5]

8.pop(self, index=None)，删除列表中索引为x的表项，并返回该表项的值，若未指定索引，pop返回列表最后一项

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,] l1.pop()  # 默认最后一个元素 print(l1)

输出[1,2,3,4,5,6,'carlos',99,[3,7]]

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,] l1.pop(5)  # 移除索引5的元素 print(l1)

输出[1,2,3,4,5,'carlos',99,[3,7],5]

9.remove(self, value)，删除列表中匹配对象x的第一个元素，匹配元素时产生异常，返回None

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,88,5,102,] l1.remove(5)  # 移除匹配项5的一个元素 print(l1)

输出[1,2,3,4,6,'carlos',99,[3,7],5,88,5,102,]

10. reverse(self)，颠倒列表元素的顺序

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l1=[1,2,3,4,5,6,'carlos',99,[3,7],5,88,5,102,] l1.reverse() print(l1)

输出[102, 5, 88, 5, [3, 7], 99, 'carlos', 6, 5, 4, 3, 2, 1]

11 .sort(self, key=None, reverse=False)，对列表排序，返回none，bisect模块可用于排序列表项的添加和删除

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1 2 3

l1=[1,25,63,4,5,6,99,5,88,15,102,] l1.sort() print(l1)

输出[1, 4, 5, 5, 6, 15, 25, 63, 88, 99, 102]

  当需要一个排好序的列表副本，同时又要保留原有列表不变的正确做法如下：

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1 2 3 4 5

l1=[1,25,63,4,5,6,99,5,88,15,102,] l2=l1[:] l2.sort() print(l1) print(l2)

输出

[1, 25, 63, 4, 5, 6, 99, 5, 88, 15, 102]
[1, 4, 5, 5, 6, 15, 25, 63, 88, 99, 102]