In a1=np.linspace(1,26,6,dtype=int)
Out array([1,6,11,16,21,26])
In a1[1:3] #array[start:end]
Out array([6,11])
In a1[:5]
Out array([1,6,11,16,21])
In a1[2:]
Out array([11,16,21,26])
In a1[-1]
Out 26
In a1[-3]
Out 16
In a1[:-1]
Out array([1,6,11,16,21])
In a1[[0,1,4]] #[0,1,4]作为索引
Out array([19,6,21])
In a3=a1[[0,3,2]]
Out array([19,16,11])
In na1=np.array(np.arange(24),dtype=int).reshpae(4,6)
[[0 1 2 3 4 5]
[6 7 8 9 10 11]
[12 13 14 15 16 17]
[18 19 20 21 22 23]
In na1[:2,1:]
Out array([[1, 2, 3, 4, 5],
[7, 8, 9, 10, 11]])
In na1[[2,3],[2,4]]
Out array([14,22])
In na1[2:,[2,4]]
Out array([[14,16],
[20,22]])
na2=na1.reshape(2,3,4)
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]]])
In na2[(1,1,2)]
Out 18
In na2[[1,1,0],[0,1,2],[2,3,1]]
Out array([14,19,9])
In na2[[1,1,1],[0,1,2],[2,3,1]]
Out array([14,19,21])
原文：https://www.cnblogs.com/jackie-ding/p/14415607.html