can fill values now

date.go

@@ -345,14 +345,22 @@ func (d date) CalculateMarketSecondsBetween(start, end, marketOpen, marketClose
 }
 
 const (
+	_secondsPerHour = 60 * 60
 	_secondsPerDay  = 60 * 60 * 24
 )
 
-func (d date) Diff(t1, t2 time.Time) (days int64) {
+func (d date) DiffDays(t1, t2 time.Time) (days int) {
 	t1n := t1.Unix()
 	t2n := t2.Unix()
-	diff := t1n - t2n
+	diff := t2n - t1n //yields seconds
-	return diff / (_secondsPerDay)
+	return int(diff / (_secondsPerDay))
+}
+
+func (d date) DiffHours(t1, t2 time.Time) (hours int) {
+	t1n := t1.Unix()
+	t2n := t2.Unix()
+	diff := t2n - t1n //yields seconds
+	return int(diff / (_secondsPerHour))
 }
 
 // NextDay returns the timestamp advanced a day.
@@ -386,3 +394,33 @@ func (d date) NextDayOfWeek(after time.Time, dayOfWeek time.Weekday) time.Time {
 	dayDelta := 7 - int(afterWeekday-dayOfWeek)
 	return after.AddDate(0, 0, dayDelta)
 }
+
+// Start returns the earliest (min) time in a list of times.
+func (d date) Start(times []time.Time) time.Time {
+	if len(times) == 0 {
+		return time.Time{}
+	}
+
+	start := times[0]
+	for _, t := range times[1:] {
+		if t.Before(start) {
+			start = t
+		}
+	}
+	return start
+}
+
+// Start returns the earliest (min) time in a list of times.
+func (d date) End(times []time.Time) time.Time {
+	if len(times) == 0 {
+		return time.Time{}
+	}
+
+	end := times[0]
+	for _, t := range times[1:] {
+		if t.After(end) {
+			end = t
+		}
+	}
+	return end
+}

date_test.go

@@ -236,3 +236,53 @@ func TestDateIsNYSEHoliday(t *testing.T) {
 	}
 	assert.Equal(holidays, 55)
 }
+
+func TestTimeStart(t *testing.T) {
+	assert := assert.New(t)
+
+	times := []time.Time{
+		time.Now().AddDate(0, 0, -4),
+		time.Now().AddDate(0, 0, -2),
+		time.Now().AddDate(0, 0, -1),
+		time.Now().AddDate(0, 0, -3),
+		time.Now().AddDate(0, 0, -5),
+	}
+
+	assert.InTimeDelta(Date.Start(times), times[4], time.Millisecond)
+}
+
+func TestTimeEnd(t *testing.T) {
+	assert := assert.New(t)
+
+	times := []time.Time{
+		time.Now().AddDate(0, 0, -4),
+		time.Now().AddDate(0, 0, -2),
+		time.Now().AddDate(0, 0, -1),
+		time.Now().AddDate(0, 0, -3),
+		time.Now().AddDate(0, 0, -5),
+	}
+
+	assert.InTimeDelta(Date.End(times), times[2], time.Millisecond)
+}
+
+func TestDateDiffDays(t *testing.T) {
+	assert := assert.New(t)
+
+	t1 := time.Date(2017, 02, 27, 12, 0, 0, 0, time.UTC)
+	t2 := time.Date(2017, 01, 10, 3, 0, 0, 0, time.UTC)
+	t3 := time.Date(2017, 02, 24, 16, 0, 0, 0, time.UTC)
+
+	assert.Equal(48, Date.DiffDays(t2, t1))
+	assert.Equal(2, Date.DiffDays(t3, t1)) // technically we should round down.
+}
+
+func TestDateDiffHours(t *testing.T) {
+	assert := assert.New(t)
+
+	t1 := time.Date(2017, 02, 27, 12, 0, 0, 0, time.UTC)
+	t2 := time.Date(2017, 02, 24, 16, 0, 0, 0, time.UTC)
+	t3 := time.Date(2017, 02, 28, 12, 0, 0, 0, time.UTC)
+
+	assert.Equal(68, Date.DiffHours(t2, t1))
+	assert.Equal(24, Date.DiffHours(t1, t3))
+}

math_util.go

@@ -148,6 +148,14 @@ func (m mathUtil) AbsInt(value int) int {
 	return value
 }
 
+// AbsInt64 returns the absolute value of a long.
+func (m mathUtil) AbsInt64(value int64) int64 {
+	if value < 0 {
+		return -value
+	}
+	return value
+}
+
 // Mean returns the mean of a set of values
 func (m mathUtil) Mean(values ...float64) float64 {
 	return m.Sum(values...) / float64(len(values))

sequence.go

@@ -155,3 +155,34 @@ func (s sequence) MarketDayMondayCloses(from, to time.Time, marketOpen, marketCl
 	}
 	return times
 }
+
+func (s sequence) Hours(start time.Time, totalHours int) []time.Time {
+	times := make([]time.Time, totalHours)
+
+	last := start
+	for i := 0; i < totalHours; i++ {
+		times[i] = last
+		last = last.Add(time.Hour)
+	}
+
+	return times
+}
+
+// HoursFill adds zero values for the data bounded by the start and end of the xdata array.
+func (s sequence) HoursFill(xdata []time.Time, ydata []float64) ([]time.Time, []float64) {
+	start := Date.Start(xdata)
+	end := Date.End(xdata)
+
+	totalHours := Math.AbsInt(Date.DiffHours(start, end))
+
+	finalTimes := s.Hours(start, totalHours+1)
+	finalValues := make([]float64, totalHours+1)
+
+	var hoursFromStart int
+	for i, xd := range xdata {
+		hoursFromStart = Date.DiffHours(start, xd)
+		finalValues[hoursFromStart] = ydata[i]
+	}
+
+	return finalTimes, finalValues
+}

sequence_test.go

@@ -43,3 +43,50 @@ func TestSequenceMarketQuarters(t *testing.T) {
 	assert.Equal(00, mh[2].Minute())
 	assert.Equal(Date.Eastern(), mh[2].Location())
 }
+
+func TestSequenceHours(t *testing.T) {
+	assert := assert.New(t)
+
+	today := time.Date(2016, 07, 01, 12, 0, 0, 0, time.UTC)
+	seq := Sequence.Hours(today, 24)
+
+	end := Date.End(seq)
+	assert.Len(seq, 24)
+	assert.Equal(2016, end.Year())
+	assert.Equal(07, int(end.Month()))
+	assert.Equal(02, end.Day())
+	assert.Equal(11, end.Hour())
+}
+
+func TestSequenceHoursFill(t *testing.T) {
+	assert := assert.New(t)
+
+	xdata := []time.Time{
+		time.Date(2016, 07, 01, 12, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 01, 13, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 01, 14, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 02, 4, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 02, 5, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 03, 12, 0, 0, 0, time.UTC),
+		time.Date(2016, 07, 03, 14, 0, 0, 0, time.UTC),
+	}
+
+	ydata := []float64{
+		1.1,
+		1.2,
+		1.4,
+		0.8,
+		2.1,
+		0.4,
+		0.6,
+	}
+
+	filledTimes, filledValues := Sequence.HoursFill(xdata, ydata)
+	assert.Len(filledTimes, Date.DiffHours(Date.Start(xdata), Date.End(xdata))+1)
+	assert.Equal(len(filledValues), len(filledTimes))
+
+	assert.NotZero(filledValues[0])
+	assert.NotZero(filledValues[len(filledValues)-1])
+
+	assert.NotZero(filledValues[16])
+}