MATLAB - Directly convert nominal data to numeric

Question

Is there any Matlab function to directly convert nominal data to numeric one ?

N.b that currently, and after several searches, I use NumericGroup=str2num(char(NominalGroup))

Thanks,

Answer 1

double(NominalGroup) will convert a nominal/categorical array to a double array.

Answer 2

Using the double function is dangerous because it returns the category index of the NominalValue.

Example:

color = categorical({'8','9','0'})
x = color(1)  % x = 8
z = double(x) % z = 2

I have been loking for a function that gives me z = 8.