如何检查向量的元素是否位于 Numpy 中的两个向量之间？

Question

Let's say A and B are given vectors and the aim is to check which elements of Y lie between A and B. For example:

A=np.array([1,2,3,4])
B=np.array([10,20,30,40])
Y=np.array([8,15,0,50])

The expected output should look like: [1,1,0,0] where the elements are not bool type so I can find out the number of true values, using np.sum()

Answer 1

You can so both comparisons and take the elementwise and

(A < Y) & (Y < B)

A np.sum() will work regardless of them being boolean. When in doubt, just cast to int using

X.astype(int)

Answer 2

It's as simple as

np.logical_and(A <= Y, Y <= B).astype(int)

But you can also sum a logical vector, numpy will handle the conversion under the hood.

In [1]: np.sum(np.logical_and(A <= Y, Y <= B).astype(int)) == np.sum(np.logical_and(A <= Y, Y <= B))
Out[1]: True