Johannes Loehnert wrote:

Hi,

I posted this before on scipy-user, maybe that was the wrong place.

Have a look at this:

# ===================================== In [1]: import numpy

In [2]: numpy.__version__ Out[2]: '0.9.7.2484'

In [3]: a = numpy.array([[0, 1],[2, 3], [4, 5],[6, 7],[8, 9]])

In [4]: b = numpy.array([False, True, True, True, False])

In [5]: a[b] Out[5]: array([[2, 3], [4, 5], [6, 7]])

In [6]: a[b,:] --------------------------------------------------------------------------- exceptions.IndexError Traceback (most recent call last)

/home/jloehnert/<console>

IndexError: arrays used as indices must be of integer type

In [7]: a[numpy.nonzero(b),:] Out[7]: array([[2, 3], [4, 5], [6, 7]]) # ======================

Is there a reason to forbid a[b, :] with boolean array b?

I think admitting this behavior would require even more checks in already complicated code. I'm not sure it's worth it. I don't have an principled opposition, but it's not on my list of things to implement. -Travis