Deleting last values in array (using Numpy)

Question

I have an Array[0] with len(Array[0]) = 40 I want to delete the last 3 values in this array.

np.delete(Array[0],[36,39])

Works as it should. However,

np.delete(Array[0],[len(Array[0])-4,len(Array[0])-1])

Deletes only the last number (instead of the last 3).

np.delete(Array[0],[-3,-1])

Doesn't do anything and gives me the warning: main :1: FutureWarning: in the future negative indices will not be ignored by numpy.delete .

What is the correct way to do this?

Answer 1

You could use range(37, 40) along with axis keyword argument to delete the last three columns. Here is a contrived example:

In [88]: arr = np.random.random_sample((3, 10))
In [89]: arr.shape
Out[89]: (3, 10)

In [90]: new_arr = np.delete(arr, range(7, 10), axis=1)

In [91]: new_arr.shape
Out[91]: (3, 7)

Please note that numpy.delete() would return a new sub-array. If you're wary of memory requirements, you should slice as Divakar suggested .

sliced_arr = Array[0][:-3]

But then you've to be careful when you modify the sliced array since that's a view of the original array.