One Row Becomes One-Hot - Categorical Features, Exactly

A single color token becomes exact integer indicators.

highlighted = computed this step

Read row A

Row A has color red. In the pinned column order, the red indicator is 1 and the other indicators are 0.

A_{\text{red}}=(1,0,0,0)

For a known category row, exactly one known-category column gets 1. The other column stays 0.

1 + 0 + 0 + 0 = 1

The word red is not turned into meaning. It is matched to the pinned red column.

\text{red token}\rightarrow\text{red indicator}