零基础学python-8.3 列表的索引、分片和矩阵
索引：注意：如果超出长度，则报错
如果索引为负数，则取数的方向反转
>>> aList=['123',123,123.0]
>>> aList
'123'
>>> aList
123.0
>>> aList[-2]
123
>>> aList[-3]
'123'
>>> aList
Traceback (most recent call last):
File "<pyshell#25>", line 1, in <module>
aList
IndexError: list index out of range
分片：
注意：如果是负数，取值会出现变化
>>> aList=['123',123,123.0]
>>> aList
['123']
>>> aList
>>> aList
['123', 123, 123.0]
>>> aList[-1:4]
>>> aList[-1:0]
[]
>>> aList[-1:1]
[]
>>>
>>> aList[-1:5]
>>> aList[-1:7]
>>> aList[-3:4]
['123', 123, 123.0]
>>>
矩阵：类似于java的多维数组
>>> matrix=[,['a','b'],[('ttt')]]
>>> matrix
['a', 'b']
>>> matrix
'ttt'
>>> matrix
'b'
>>>
就说到这里，谢谢大家
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