[python日志]2019年1月10日 20:36:58

版权声明： https://blog.csdn.net/weixin_38272395/article/details/86255133

创建列表

>>> member = ['AAA','BB','CC','DDD']
>>> member
['AAA', 'BB', 'CC', 'DDD']

>>> number = [1,2,3,4]
>>> number
[1, 2, 3, 4]

>>> mix = [1,'AAA',1.0011,[1,2,3]]
>>> mix
[1, 'AAA', 1.0011, [1, 2, 3]]

>>> empty = []
>>> empty
[]

向列表添加元素

>>> member.append('ZZZZ')
>>> member
['AAA', 'BB', 'CC', 'DDD', 'ZZZZ']
>>> len(member)
5

append同时只能添加一个
>>> member.append('11111','22222')
Traceback (most recent call last):
  File "<pyshell#11>", line 1, in <module>
    member.append('11111','22222')
TypeError: append() takes exactly one argument (2 given)


extend的参数是列表
>>> member.extend('11111','22222')
Traceback (most recent call last):
  File "<pyshell#12>", line 1, in <module>
    member.extend('11111','22222')
TypeError: extend() takes exactly one argument (2 given)
>>> member.extend(['11111','22222'])
>>> member
['AAA', 'BB', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> len(member)
7

insert(位置,参数)
>>> member.insert(1,'SSSSS')
>>> member
['AAA', 'SSSSS', 'BB', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> len(member)
8



>>> member[0]
'AAA'
>>> member[1]
'SSSSS'
>>> temp = member[0]
>>> member[0] = member[1]
>>> member
['SSSSS', 'SSSSS', 'BB', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> member[1] = temp
>>> member
['SSSSS', 'AAA', 'BB', 'CC', 'DDD', 'ZZZZ', '11111', '22222']

从列表删除元素

remove(item)方法是直接对可变序中的元素进行检索删除，返回的是删除后的列表,不返回删除值（返回None）
>>> member.remove('BB')
>>> member
['SSSSS', 'AAA', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> member.remove('454')
Traceback (most recent call last):
  File "<pyshell#29>", line 1, in <module>
    member.remove('454')
ValueError: list.remove(x): x not in list
>>> 


del(list[index])方法是对可变序列中元素下边进行检索删除，不返回删除值
>>> del member[1]
>>> member
['SSSSS', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> mix
[1, 'AAA', 1.0011, [1, 2, 3]]
>>> del mix
>>> mix
Traceback (most recent call last):
  File "<pyshell#34>", line 1, in <module>
    mix
NameError: name 'mix' is not defined
>>> 


pop(index)方法是对可变序列中元素下标进行检索删除，返回删除值
>>> member
['SSSSS', 'CC', 'DDD', 'ZZZZ', '11111', '22222']
>>> member.pop()
'22222'
>>> member
['SSSSS', 'CC', 'DDD', 'ZZZZ', '11111']
>>> member.pop(1)
'CC'
>>> member
['SSSSS', 'DDD', 'ZZZZ', '11111']
>>> 

列表分片(Slice)

 下标包头不包尾

>>> member[1:3]
['DDD', 'ZZZZ']
>>> member[:3]
['SSSSS', 'DDD', 'ZZZZ']
>>> member[0:]
['SSSSS', 'DDD', 'ZZZZ', '11111']

>>> member2 = member[:]
>>> member2
['SSSSS', 'DDD', 'ZZZZ', '11111']
>>> member
['SSSSS', 'DDD', 'ZZZZ', '11111']
>>> 

列表的一些常用操作符

#比较操作符
#逻辑操作符
#连接操作符
#重复操作符
#成员关系操作符

>>> list1 = [123]
>>> list2 = [234]
>>> list1 > list2
False
>>> list1
[123]
>>> list1 = [123,456]
>>> list2 = [234,123]
>>> list1 > list2
False
>>> list3 = [123,456]
>>> (list1 < list2) and (list1 == list3)
True
#####################################################################
>>> list4 = list1 + list2
>>> list4
[123, 456, 234, 123]
#####################################################################
>>> list1 + "111"
Traceback (most recent call last):
  File "<pyshell#11>", line 1, in <module>
    list1 + "111"
TypeError: can only concatenate list (not "str") to list
>>> list3
[123, 456]
#####################################################################
>>> list3 * 3
[123, 456, 123, 456, 123, 456]
>>> list3
[123, 456]
>>> list3 *= 3
>>> list3
[123, 456, 123, 456, 123, 456]
#####################################################################
>>> 999 in list3
False
>>> 999 not in list3
True

>>> list5 = [123,['111','222'],456]
>>> '111' in list5
False
>>> '111' in list5[1]
True

>>> list5[1][1]
'222'
>>> 

列表相关

>>> list3
[123, 456, 123, 456, 123, 456]
>>> list3.count(123)
3            #出现过三次
>>> list3.count(111)
0
>>> 



>>> list3.index(456)
1
>>> list3.index(3)
Traceback (most recent call last):
  File "<pyshell#30>", line 1, in <module>
    list3.index(3)
ValueError: 3 is not in list
>>> list3.index(123,3,6)                #查找的对象，开始位置，结束位置
4
>>> 

>>> list3.reverse()
>>> list3
[456, 123, 456, 123, 456, 123]
>>> 


>>> list6 = [4,2,5,1,9,21,43,0]
>>> list6
[4, 2, 5, 1, 9, 21, 43, 0]
>>> list6.sort()
>>> list6
[0, 1, 2, 4, 5, 9, 21, 43]
>>> list6.sort(reverse=True)
>>> list6
[43, 21, 9, 5, 4, 2, 1, 0]
>>> 

某大佬的sort方法详解：https://blog.csdn.net/lianshaohua/article/details/80483357

                       （学习学习）

 

一个问题：

>>> list7 = list6
>>> list7
[43, 21, 9, 5, 4, 2, 1, 0]
>>> list8 = list6[:]
>>> list8
[43, 21, 9, 5, 4, 2, 1, 0]
>>> list6.sort()
>>> list6
[0, 1, 2, 4, 5, 9, 21, 43]
>>> list7
[0, 1, 2, 4, 5, 9, 21, 43]
>>> list8
[43, 21, 9, 5, 4, 2, 1, 0]
>>>