[Numpy-discussion] masked arrays

[John Hunter]

I'm a bit of an ma newbie.  I have a 2D masked array R and want to
extract the non-masked values in the last column.  Below I use logical
indexing, but I suspect there is a "built-in" way w/ masked arrays.  I
read through the docstring, but didn't see anything better.

In [66]: c = R[:,-1]

In [67]: m = R.mask[:,-1]


In [69]: c[m==0]
Out[69]:
array(data =
 [ 0.94202899  0.51839465  0.24080268  0.26198439  0.29877369
 2.06856187
  0.91415831  0.64994426  0.96544036  1.11259755  2.53623188
  0.71571906
  0.18394649  0.78037904  0.60869565  3.56744705  0.44147157
  0.07692308
  0.27090301  0.16610925  0.57068004  0.80267559  0.57636566
  0.23634337
  1.9509476   0.50761427  0.09587514  0.45039019  0.14381271
  0.69007804
  2.44481605  0.2909699   0.45930881  1.37123746  2.00668896
  3.1638796
  1.0735786   1.06800446  0.18952062  1.55964326  1.16833891
  0.17502787
  1.16610925  0.85507246  0.42140468  0.04236343  1.01337793
  0.22853958
  1.76365663  1.78372352  0.96209588  0.73578595  0.94760312
  1.59531773
  0.88963211],
      mask =
 [False False False False False False False False False False False
 False
 False False False False False False False False False False False
 False
 False False False False False False False False False False False
 False
 False False False False False False False False False False False
 False
 False False False False False False False],
      fill_value=1e+20)