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
l2=[1,2,3,4,5,6,] l2[3]=78 print(l2)
输出[1, 2, 3, 78, 5, 6]
l2=[1,2,3,4,5,6,] l2[4]='xyz' print(l2)
输出[1, 2, 3, 4, 'xyz', 6]
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]
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
list=[1,2,3,4,5,] list.append(88) print(list)
输出[1, 2, 3, 4, 5, 88]
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)
l1=[1,2,3,4,5,] l1.clear() print(l1)
输出[]
3. copy(self)
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
l1=['to',2,'be','to',5,]
result=l1.count('to')
print(result)
输出2
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
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
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
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
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
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
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]]
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
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
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
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：
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]