python列表三

　　

>>> list1 = [123]
>>> list2 =[234]
>>> list1 > list2
False
>>> list1 = [123,456]
>>> list2 = [456,123]
>>> list3 = [234,123]
>>> (list1<list2)and(list1 == list3)
False
>>> list3= [123,456]
>>> (list1<list2)and(list1 == list3)
True
>>> list4 = list1 + list2
>>> list4
[123, 456, 456, 123]
>>>

>>> list3
[123, 456]
>>> list3* 3
[123, 456, 123, 456, 123, 456]
>>> list3 *= 3
>>> list3
[123, 456, 123, 456, 123, 456]
>>>

>>> list3
[123, 456, 123, 456, 123, 456]
>>> 123 in list3
True
>>> "li" not in list3
True
>>>

>>> list5 = [123,456,["小虎","小胡","小尹"]]
>>> "小虎"in list5
False

>>> "小虎"in list5[2]
True
>>>

list[2][1]
TypeError: 'type' object is not subscriptable
>>> list5[2][1]
'小胡'
>>>

count计算出现的次数

>>> list3.count(123)
3
>>> list3
[123, 456, 123, 456, 123, 456]
>>> list3 *= 5
>>> list3
[123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456]
>>> list3.count(123)
15
>>>

index出现元素的值的下标

>>> list3
[123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456, 123, 456]
>>> list3.index(123)
0
>>> list3.index(123,3,6)
4
>>>

reserve（重要）反转

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

sort（最重要）排序，默认归并排序

>>> list6 = [0,5,1,2,4,9,6,7,3]
>>> list6.sort()
>>> list6
[0, 1, 2, 3, 4, 5, 6, 7, 9]
>>> list6.sort(reverse=True)
>>> list6
[9, 7, 6, 5, 4, 3, 2, 1, 0]
>>>

注意 ： list7 = list6[:] ，使用分片来拷贝列表，原来列表排序对拷贝后的列表没有影响，如果使用=来复制列表，则原来列表排序后对复制后的列表有影响

>>> list6
[9, 7, 6, 5, 4, 3, 2, 1, 0]
>>> list7 = list6[:]
>>> list7
[9, 7, 6, 5, 4, 3, 2, 1, 0]
>>> list8 = list6
>>> list8
[9, 7, 6, 5, 4, 3, 2, 1, 0]
>>> list6.sort()
>>> list6
[0, 1, 2, 3, 4, 5, 6, 7, 9]
>>> list7
[9, 7, 6, 5, 4, 3, 2, 1, 0]
>>> list8
[0, 1, 2, 3, 4, 5, 6, 7, 9]
>>>