Question

Let an array:

 a =np.array([[1,2],[3,-5],[6,-15],[10,7]])

to get lines with elements of the second column above -6 it’ s possible to do

>>> a[a[:,1]>-6]
array([[ 1,  2],
   [ 3, -5],
   [10,  7]])

but how to get lines with the second element between -6;3?
I tried:

>>> a[3>a[:,1]>-6]

and also (which raises an error):

>>> np.ma.masked_inside(a,-6,3)

which gives:

 masked_array(data =
 [[-- --]
  [-- --]
  [6 -15]
  [10 7]],
         mask =
  [[ True  True]
  [ True  True]
  [False False]
  [False False]],
   fill_value = 999999)

but the result is not too clear

Thanks
jp

Answer 1

>>> a[ (-6<a[:,1]) & (a[:,1]<3) ]

array([[ 1,  2],
       [ 3, -5]])