if i have an array
a = np.array([[1,2,3],[4,5,6],[7,8,9]])
output would be a =[1,2,3],[4,5,6],[7,8,9]
using slice [start:endindex:stepindex], how could i retrieve 3 and 7?
is it possible?
I have tried
a[:3:2]
this gave me 1rst row and third row
In [928]: a = np.array([[1,2,3],[4,5,6],[7,8,9]])
In [929]: a
Out[929]:
array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]])
[3,7] isn't regular pattern in this 2d array. But its flattened view:
In [931]: a.ravel()
Out[931]: array([1, 2, 3, 4, 5, 6, 7, 8, 9])
In [932]: a.ravel()[2::4]
Out[932]: array([3, 7])
In [933]: a.flat[2::4]
Out[933]: array([3, 7])
Now guarantee that it can be extended for larger arrays and selections.
