Numpy: find index of the elements within range

Question

I have a numpy array of numbers, for example,

a = np.array([1, 3, 5, 6, 9, 10, 14, 15, 56])  

I would like to find all the indexes of the

Answer 1

Other way is with:

np.vectorize(lambda x: 6 <= x <= 10)(a)

which returns:

array([False, False, False,  True,  True,  True, False, False, False])

It is sometimes useful for masking time series, vectors, etc.