[source] # Hold Out Hold Out is a quick and simple cross validation technique that uses a validation set that is *held out* from the training data. The advantages of Hold Out is that the validation score is quick to compute, however it does not allow the learner to *both* train and test on all the data in the training set. **Interfaces:** [Validator](api.md#validator) ## Parameters | # | Name | Default | Type | Description | |---|---|---|---|---| | 1 | ratio | 0.2 | float | The ratio of samples to hold out for testing. | ## Example ```php use Rubix\ML\CrossValidation\HoldOut; $validator = new HoldOut(0.3); ```