Masked array set slice fails with np.ma.masked on right side #8624

Activity

1. taldcroft commented on Feb 16, 2017

   

   taldcroft

   on Feb 16, 2017

   Author

   More actions

   Interestingly, this works as expected:

   In [1]: x = np.ma.MaskedArray([1,2,3])
   In [2]: x[:2] = np.ma.asarray([100, np.ma.masked], dtype=int)
   In [3]: x
   Out[3]: 
   masked_array(data = [100 -- 3],
                mask = [False  True False],
          fill_value = 999999)
   
2. eric-wieser

   added

   component: numpy.mamasked arraysmasked arrays

   on Feb 19, 2017
3. eric-wieser commented on Feb 23, 2017

   

   eric-wieser

   on Feb 23, 2017

   Member

   More actions

   A related bug came up in #8510, which I'll repeat here since that wasn't the focus of that issue:

   >>> arr = np.ma.arange(5)
   >>> arr[1:3] = [1, np.ma.masked]
   ValueError: setting an array element with a sequence.
   
   #expected result:
   >>> arr
   masked_array(data = [0 1 -- 3 4],
                mask = [False False  True False False],
          fill_value = 999999)
4. eric-wieser commented on Feb 23, 2017

   

   eric-wieser

   on Feb 23, 2017

   Last edited by eric-wieser

   Member

   More actions

   Your code fails in the same way as the above for me on both master and 1.11.1
5. sethtroisi commented on Sep 17, 2019

   

   sethtroisi

   on Sep 17, 2019

   Contributor

   More actions

   This no longer reproduces and this problem is "fixed"

   >>> x = np.ma.MaskedArray([1,2,3])
   >>> x[:2] = [100, np.ma.masked]
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 3323, in __setitem__
       _data[indx] = dval
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 4312, in __int__
       raise MaskError('Cannot convert masked element to a Python int.')
   numpy.ma.core.MaskError: Cannot convert masked element to a Python int.

   >>> x = np.ma.MaskedArray([1,2,3])
   >>> x[:2] = np.ma.asarray([100, np.ma.masked], dtype=int)
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 7771, in asarray
       subok=False, order=order)
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 2788, in __new__
       order=order, subok=True, ndmin=ndmin)
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 4312, in __int__
       raise MaskError('Cannot convert masked element to a Python int.')
   numpy.ma.core.MaskError: Cannot convert masked element to a Python int.

   >>> arr = np.ma.arange(5)
   >>> arr[1:3] = [1, np.ma.masked]
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 3323, in __setitem__
       _data[indx] = dval
     File "/usr/local/lib/python3.6/dist-packages/numpy/ma/core.py", line 4312, in __int__
       raise MaskError('Cannot convert masked element to a Python int.')
   numpy.ma.core.MaskError: Cannot convert masked element to a Python int.