What are the possible feature types in xgboost?

Question

On the documentation page for xgboost for python we see a feature_types https://xgboost.readthedocs.io/en/latest/python/python_api.html parameters but have no idea what are the possible values.

The documentation is really bad.

What are the possible values for feature_types?

Answer 1

The documentation seems poor as you say, searching through the XGBoost source code on Github gives some tests that show these options:

• int
• float
• q: quantitative
• i: indicator

While it is a bit difficult to figure out what these mean, some other sites list some additional information:

• i: "i means this feature is binary indicator feature"
• q: "means this feature is a quantitative value, such as age, time, can be missing"
• int: "means this feature is integer value (when int is hinted, the decision boundary will be integer)"

Link: another StackOverflow post that mentions the q and i types.

In XGBoosts core.py code you can also find a comment on types:

 # use quantitative as default
 # {'q': quantitative, 'i': indicator}

Looking at the XGBoost code, from the rest of it, the type parsing goes into the underlying c-based backend code, so that is a bit of a black box still unless you want to go explore it.. :)