python - Numpy array, fill empty values for a single column

Question

I have an array in numpy, which was generated using np.array() from a python list so my entries are strings, but some of the values are blank. Here is an example array:

['1', '1', '1', '1']
['1', '1', '', '1']
['1', '1', '1', '1']
['1', '', '1', '1']

There is no 'NaN' or 'None', it is blank. I want to be able to fill all the blank cells in a particular column with the same value.

Answer 1

You can use numpy.where() to achieve this.

In [8]: arr = numpy.array(['','1','2','3',''])

In [9]: arr[numpy.where(arr=='')] = '0'

In [10]: arr
Out[10]:
array(['0', '1', '2', '3', '0'],
      dtype='|S1')

Edit As @mgilson pointed out, you could just do:

arr[arr==''] = '0'