I’ve got various 3D arrays that I’m viewing 2D slices of, along either the X, Y or Z axis.
To simplify my code, I would like to have one location of declaring the slice such as
# X View my_view = [10, :, :] # Y View # my_view = [:, 4, :] # Z View # my_view = [:, :, 7]
and choose which view to run in my script.
Then the rest of my code can apply the myview slice when visualizing,
plt.plot(my_data[myview]) plt.plot(more_data[myview])
There’s no way to “store” the ‘:’ portion of the slice. How would I accomplish this in Python/Numpy?
Advertisement
Answer
np.s_ is a handy tool for making an indexing tuple:
In [21]: np.s_[10,:,:] Out[21]: (10, slice(None, None, None), slice(None, None, None))
but you can create that directly:
In [22]: (10,slice(None),slice(None)) Out[22]: (10, slice(None, None, None), slice(None, None, None))
arr[i,j] is the same as arr[(i,j)], the comma creates a tuple.
In [23]: 10,slice(None),slice(None) Out[23]: (10, slice(None, None, None), slice(None, None, None))
You can create a more general indexing tuple this way.