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