forked from golang/hotime
45 lines
1.0 KiB
Go
45 lines
1.0 KiB
Go
package stats
|
|
|
|
// Outliers holds mild and extreme outliers found in data
|
|
type Outliers struct {
|
|
Mild Float64Data
|
|
Extreme Float64Data
|
|
}
|
|
|
|
// QuartileOutliers finds the mild and extreme outliers
|
|
func QuartileOutliers(input Float64Data) (Outliers, error) {
|
|
if input.Len() == 0 {
|
|
return Outliers{}, EmptyInput
|
|
}
|
|
|
|
// Start by sorting a copy of the slice
|
|
copy := sortedCopy(input)
|
|
|
|
// Calculate the quartiles and interquartile range
|
|
qs, _ := Quartile(copy)
|
|
iqr, _ := InterQuartileRange(copy)
|
|
|
|
// Calculate the lower and upper inner and outer fences
|
|
lif := qs.Q1 - (1.5 * iqr)
|
|
uif := qs.Q3 + (1.5 * iqr)
|
|
lof := qs.Q1 - (3 * iqr)
|
|
uof := qs.Q3 + (3 * iqr)
|
|
|
|
// Find the data points that are outside of the
|
|
// inner and upper fences and add them to mild
|
|
// and extreme outlier slices
|
|
var mild Float64Data
|
|
var extreme Float64Data
|
|
for _, v := range copy {
|
|
|
|
if v < lof || v > uof {
|
|
extreme = append(extreme, v)
|
|
} else if v < lif || v > uif {
|
|
mild = append(mild, v)
|
|
}
|
|
}
|
|
|
|
// Wrap them into our struct
|
|
return Outliers{mild, extreme}, nil
|
|
}
|