What has to be done to text input for ANN?

exposure_types = {'acid', 'alkaline', 'alkaline+salt', 'water'};

and input data is something like this

inputs = {'acid', 'acid', 'acid', 'water', 'alkaline', 'acid', 'alkaline+salt'}

you can get an equivalent numeric form using ismember()

[~, inputs_numeric] = ismember(inputs, exposure_types);<?pre>

Result

>> inputs_numeric
inputs_numeric =
     1     1     1     4     2     1     3