numpy/numpy — pull request #2733 by astrofrog (2012-11-13 15:23:40+00:00)
Title: Fix setting of fill_value for string columns in Python 3

As first discovered in astropy/astropy#451 by @taldcroft, there is a bug with setting the fill value of a string array in MaskedArray with Python 3.x:

```python
In [37]: d = ma.array(['w', 'y', 'z'], mask=[1,0,0])

In [38]: d
Out[38]:
masked_array(data = [-- y z],
mask = [ True False False],
fill_value = N/A)

In [39]: d.fill_value='X'

In [40]: d
Out[40]:
masked_array(data = [-- y z],
mask = [ True False False],
fill_value = N/A)
```

The attached code fixes this.