Unknown Category Goes to Other - Categorical Features, Exactly

A new category token uses the pinned other-column policy.

highlighted = computed this step

Show the new token

Row D has color yellow. Yellow is not in the pinned known list red, blue, green.

D_{\text{color}}=\text{yellow}

The policy is pinned: unknown category goes to the other column. Row D becomes red 0, blue 0, green 0, other 1.

D_{\text{yellow}}=(0,0,0,1)

The lesson chooses the other-column policy before encoding. A different policy would be a different pinned lesson.

\text{unknown category}\rightarrow\text{other column}