Converting empty strings to 0 using Numpy

Question

I have a numpy array where each element looks something like this:

[\'3\' \'1\' \'35\' \'0\' \'0\' \'8.05\' \'2\']
[\'3\' \'1\' \'\' \'0\' \'0\' \'8.4583\' \         


        

Answer 1

Here is an approach that uses map:

def FloatOrZero(value):
    try:
        return float(value)
    except:
        return 0.0


print map(FloatOrZero, ['3', '1', '', '0', '0', '8.4583', '0'])

Outputs:

[3.0, 1.0, 0.0, 0.0, 0.0, 8.4583, 0.0]

In case you needed more flexibility

Answer 2

Just do this first:

s = np.array(['1', '0', ''])
s[s==''] = '0'

s.astype(float)
#array([ 1.,  0.,  0.])

Answer 3

If your array is t:

t[t=='']='0'

and then convert it.

Explanation:

t=='' creates a boolean array with the same shape as t that has a True value where the corresponding t value is an empty space. This boolean array is then used to assign '0' only to the appropriate indices in the original t.