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