import numpy as npdata2=[[8.5,6,4.1,2,0.7],[1.5,3,5.4,7,3.9],[3.2,4.5,6,3,9]]
arr2=np.array(data2)
# array([[8.5, 6. , 4.1, 2. , 0.7],[1.5, 3. , 5.4, 7. , 3.9],[3.2, 4.5, 6. , 3. , 9. ]])arr2[[2,1]]
# array([[3.2, 4.5, 6. , 3. , 9. ],[1.5, 3. , 5.4, 7. , 3.9]])arr2[[2,2],[0,1]] # arr2[2,0] arr2[2,1]
# array([3.2, 4.5])arr2[:,[3,1]]
array([[2. , 6. ],[7. , 3. ],[3. , 4.5]])arr2[:,1]
# array([6. , 3. , 4.5])arr2[:,[1]]# array([[6. ],[3. ],[4.5]])arr2[np.ix_([0,-1],[0,1,3])]
# array([[8.5, 6. , 2. ], [3.2, 4.5, 3. ]])arr2[[0,-1]]
# array([[8.5, 6. , 4.1, 2. , 0.7],[3.2, 4.5, 6. , 3. , 9. ]])
arr2[[0,-1]][:,[0,1,3]]
# array([[8.5, 6. , 2. ],[3.2, 4.5, 3. ]])