hotime/vendor/github.com/montanaflynn/stats/quartile.go
2022-10-19 21:32:34 +08:00

75 lines
1.5 KiB
Go

package stats
import "math"
// Quartiles holds the three quartile points
type Quartiles struct {
Q1 float64
Q2 float64
Q3 float64
}
// Quartile returns the three quartile points from a slice of data
func Quartile(input Float64Data) (Quartiles, error) {
il := input.Len()
if il == 0 {
return Quartiles{}, EmptyInput
}
// Start by sorting a copy of the slice
copy := sortedCopy(input)
// Find the cutoff places depeding on if
// the input slice length is even or odd
var c1 int
var c2 int
if il%2 == 0 {
c1 = il / 2
c2 = il / 2
} else {
c1 = (il - 1) / 2
c2 = c1 + 1
}
// Find the Medians with the cutoff points
Q1, _ := Median(copy[:c1])
Q2, _ := Median(copy)
Q3, _ := Median(copy[c2:])
return Quartiles{Q1, Q2, Q3}, nil
}
// InterQuartileRange finds the range between Q1 and Q3
func InterQuartileRange(input Float64Data) (float64, error) {
if input.Len() == 0 {
return math.NaN(), EmptyInput
}
qs, _ := Quartile(input)
iqr := qs.Q3 - qs.Q1
return iqr, nil
}
// Midhinge finds the average of the first and third quartiles
func Midhinge(input Float64Data) (float64, error) {
if input.Len() == 0 {
return math.NaN(), EmptyInput
}
qs, _ := Quartile(input)
mh := (qs.Q1 + qs.Q3) / 2
return mh, nil
}
// Trimean finds the average of the median and the midhinge
func Trimean(input Float64Data) (float64, error) {
if input.Len() == 0 {
return math.NaN(), EmptyInput
}
c := sortedCopy(input)
q, _ := Quartile(c)
return (q.Q1 + (q.Q2 * 2) + q.Q3) / 4, nil
}