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statistics.go
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/
statistics.go
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package goutils
import (
"errors"
"math"
"sort"
)
// AvgFloat64 平均值
func AvgFloat64(f []float64) (float64, error) {
fl := len(f)
if fl == 0 {
return 0, errors.New("empty slice")
}
sum := float64(0)
for _, i := range f {
sum += i
}
return sum / float64(len(f)), nil
}
// VarianceFloat64 求方差
func VarianceFloat64(fs []float64) (float64, error) {
// 均值
favg, err := AvgFloat64(fs)
if err != nil {
return 0, err
}
variance := float64(0)
for _, f := range fs {
variance += math.Pow(f-favg, 2)
}
fsLen := len(fs)
if fsLen < 2 {
return variance, nil
}
variance = variance / (float64(len(fs) - 1))
return variance, nil
}
// StdDeviationFloat64 求标准差
func StdDeviationFloat64(fs []float64) (float64, error) {
v, err := VarianceFloat64(fs)
if err != nil {
return 0, err
}
return math.Sqrt(v), nil
}
// MidValueFloat64 获取中位数
func MidValueFloat64(values []float64) (float64, error) {
vlen := len(values)
if vlen == 0 {
return 0, errors.New("no data")
}
sort.Float64s(values)
mid := vlen / 2
if vlen%2 == 0 {
return (values[mid-1] + values[mid]) / 2.0, nil
}
return values[mid], nil
}