How to preprocess an ordered categorical variable to feed a machine learning algorithm?

I have a categorical variable that measures the income of a family:

A: no income
B: Up to $500 C:$500-$700 … P:$5000-$6000 Q: More than \\\$6000


It seems odd to me that I have to get dummies for this variable, since it's ordered. I wonder if it's better to map the values: {'A': 0, 'B': 1, …, 'Q': 17} so I can input it into the algorithm this values as integer numbers.

What's the proper way of preprocessing this variable to feed an algorithm such as Random Forest or a simple neural network?

• I have come across "ordinal classification" algorithms, such as ordinal SVM. I suppose those libraries have their own input suggestions. Unfortunately, I am not aware of one at the moment. The next best thing I believe would be to do a regression. – Grzegorz Aug 20 at 21:01