remove ginext/mongoext (no-dep lib)

mathext/statistics.go

@@ -0,0 +1,41 @@
+package mathext
+
+func Sum(v []float64) float64 {
+	total := float64(0)
+	for _, v := range v {
+		total += v
+	}
+	return total
+}
+
+func Mean(v []float64) float64 {
+	return Sum(v) / float64(len(v))
+}
+
+func Median(v []float64) float64 {
+	if len(v)%2 == 1 {
+		return v[len(v)/2]
+	} else {
+		return (v[len(v)/2-1] + v[len(v)/2]) / float64(2)
+	}
+}
+
+func Min(v []float64) float64 {
+	r := v[0]
+	for _, val := range v {
+		if val < r {
+			r = val
+		}
+	}
+	return r
+}
+
+func Max(v []float64) float64 {
+	r := v[0]
+	for _, val := range v {
+		if val > r {
+			r = val
+		}
+	}
+	return r
+}