php-ml/docs/machine-learning/classification/knearestneighbors.md

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2016-04-08 22:36:48 +00:00
# KNearestNeighbors Classifier
Classifier implementing the k-nearest neighbors algorithm.
### Constructor Parameters
* $k - number of nearest neighbors to scan (default: 3)
```
$classifier = new KNearestNeighbors($k=4);
```
### Train
To train a classifier simply provide train samples and labels (as `array`):
```
$samples = [[1, 3], [1, 4], [2, 4], [3, 1], [4, 1], [4, 2]];
$labels = ['a', 'a', 'a', 'b', 'b', 'b'];
$classifier = new KNearestNeighbors();
$classifier->train($samples, $labels);
```
### Predict
To predict sample class use `predict` method. You can provide one sample or array of samples:
```
$classifier->predict([3, 2]);
// return 'b'
$classifier->predict([[3, 2], [1, 5]]);
// return ['b', 'a']
```