# Categorical data

> Features having a specific set of possible values. For example, consider a categorical feature named `traffic-light-state`, which can only have one of the following three possible values:

[Features](https://wiki.g15e.com/pages/Feature%20(machine%20learning.txt)) having a specific set of possible values. For example, consider a categorical feature named `traffic-light-state`, which can only have one of the following three possible values:

- `red`
- `yellow`
- `green`

By representing `traffic-light-state` as a categorical feature, a model can learn the differing impacts of `red`, `green`, and `yellow` on driver behavior.

## See also

- [Numerical data](https://wiki.g15e.com/pages/Numerical%20data.txt)
- [ML crash course - Categorical data](https://wiki.g15e.com/pages/ML%20crash%20course%20-%20Categorical%20data.txt)