go-chart/sequence.go

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2016-07-30 03:24:25 +02:00
package chart
import (
"math/rand"
"time"
)
var (
// Sequence contains some sequence utilities.
// These utilities can be useful for generating test data.
Sequence = &sequence{}
)
type sequence struct{}
// Float64 produces an array of floats from [start,end] by optional steps.
func (s sequence) Float64(start, end float64, steps ...float64) []float64 {
var values []float64
step := 1.0
if len(steps) > 0 {
step = steps[0]
}
if start < end {
for x := start; x <= end; x += step {
values = append(values, x)
}
} else {
for x := start; x >= end; x = x - step {
values = append(values, x)
}
}
return values
}
// Random generates a fixed length sequence of random values between (0, scale).
func (s sequence) Random(samples int, scale float64) []float64 {
rnd := rand.New(rand.NewSource(time.Now().Unix()))
values := make([]float64, samples)
for x := 0; x < samples; x++ {
values[x] = rnd.Float64() * scale
}
return values
}
// Days generates a sequence of timestamps by day, from -days to today.
func (s sequence) Days(days int) []time.Time {
var values []time.Time
for day := days; day >= 0; day-- {
values = append(values, time.Now().AddDate(0, 0, -day))
}
return values
}