一维数据的索引和切片：与python列表类似
>>>a = np.array([1,2,3,4,5]) >>>a[2]#索引 3 >>>a[1:4:2]#切片 array([2,4])多维数组的索引和切片：
>>>a = np.arange(24).reshape((2,3,4)) >>>a array([[[ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11]], [[12, 13, 14, 15], [16, 17, 18, 19], [20, 21, 22, 23]]]) >>>a[1,2,3]#索引：从高维向低维约束 23 >>>a[0,1,2] 6 >>>a[:,1,-3]#切片：与一维类似在每一个维度上切片 array([5,17]) >>>a[:,:,::2] array([[[ 0, 2], [ 4, 6], [ 8, 10]], [[12, 14], [16, 18], [20, 22]]])