add variance option

ch1aki · May 22, 2020 · aedab9f · aedab9f
1 parent 02774a3
commit aedab9f
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Showing 3 changed files with 39 additions and 16 deletions.
diff --git a/lib/st.go b/lib/st.go
@@ -16,6 +16,7 @@ type St struct {
 	Sum       bool
 	Mean      bool
 	Stddev    bool
+	Variance  bool
 
 	count    int64
 	min      float64
@@ -58,7 +59,7 @@ func (s *St) Output(writer io.Writer) {
 	header := []string{}
 	data := []string{}
 
-	defaults := !(s.Count || s.Min || s.Max || s.Sum || s.Mean || s.Stddev)
+	defaults := !(s.Count || s.Min || s.Max || s.Sum || s.Mean || s.Stddev || s.Variance)
 
 	if defaults || s.Count {
 		header = append(header, "N")
@@ -84,6 +85,10 @@ func (s *St) Output(writer io.Writer) {
 		header = append(header, "STDDEV")
 		data = append(data, strconv.FormatFloat(s.stddev, 'f', -1, 64))
 	}
+	if s.Variance {
+		header = append(header, "VARIANCE")
+		data = append(data, strconv.FormatFloat(s.variance, 'f', -1, 64))
+	}
 
 	s.Formatter(writer, header, [][]string{data})
 }

diff --git a/lib/st_test.go b/lib/st_test.go
@@ -24,7 +24,7 @@ func TestSetOption(t *testing.T) {
 		t.Errorf("expected != actual\n%s\n", diff)
 	}
 }
-func TestNoOption(t *testing.T) {
+func TestDefaultOption(t *testing.T) {
 	w := new(bytes.Buffer)
 	st := St{
 		Formatter: func(writer io.Writer, header []string, data [][]string) {
@@ -39,6 +39,22 @@ func TestNoOption(t *testing.T) {
 	}
 }
 
+func TestNotDefaultOption(t *testing.T) {
+	w := new(bytes.Buffer)
+	st := St{
+		Formatter: func(writer io.Writer, header []string, data [][]string) {
+			s := []byte(strings.Join(header, ","))
+			writer.Write(s)
+		},
+		Variance: true,
+	}
+	st.Output(w)
+
+	if diff := cmp.Diff(w.String(), "VARIANCE"); diff != "" {
+		t.Errorf("expected != actual\n%s\n", diff)
+	}
+}
+
 func TestPlainTextFromatter(t *testing.T) {
 	stdout := new(bytes.Buffer)
 	st := St{

diff --git a/main.go b/main.go
@@ -12,14 +12,15 @@ import (
 )
 
 type options struct {
-	Version func() `short:"v" long:"version" description:"show version"`
-	Format  string `short:"f" long:"format" default:"%g" description:"outpuut format"`
-	Count   bool   `short:"N" long:"count" description:"sample size"`
-	Min     bool   `long:"min" description:"minimum"`
-	Max     bool   `long:"max" description:"maximum"`
-	Sum     bool   `long:"sum" description:"sum of elements of the sample"`
-	Mean    bool   `short:"m" long:"mean" description:"mean"`
-	Stddev  bool   `long:"sd" description:"standard deviation"`
+	Version  func() `short:"v" long:"version" description:"show version"`
+	Format   string `short:"f" long:"format" default:"%g" description:"outpuut format"`
+	Count    bool   `short:"N" long:"count" description:"sample size"`
+	Min      bool   `long:"min" description:"minimum"`
+	Max      bool   `long:"max" description:"maximum"`
+	Sum      bool   `long:"sum" description:"sum of elements of the sample"`
+	Mean     bool   `short:"m" long:"mean" description:"mean"`
+	Stddev   bool   `long:"sd" description:"standard deviation"`
+	Vatiance bool   `long:"variance" description:"variance"`
 }
 
 func main() {
@@ -37,12 +38,13 @@ func main() {
 	s := st.St{
 		Formatter: st.PlainTextFormatter,
 
-		Count:  opts.Count,
-		Min:    opts.Min,
-		Max:    opts.Max,
-		Sum:    opts.Sum,
-		Mean:   opts.Mean,
-		Stddev: opts.Stddev,
+		Count:    opts.Count,
+		Min:      opts.Min,
+		Max:      opts.Max,
+		Sum:      opts.Sum,
+		Mean:     opts.Mean,
+		Stddev:   opts.Stddev,
+		Variance: opts.Vatiance,
 	}
 
 	scanner := bufio.NewScanner(os.Stdin)