From 485a0e3b0b1906d40f46049912f704ce7c52ac3f Mon Sep 17 00:00:00 2001
From: wangfeng <wangfengxy@sina.cn>
Date: Sat, 4 Feb 2023 18:25:07 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E7=8B=AC=E7=AB=8Bmean=E6=96=B9=E6=B3=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 generic_rolling.go | 10 ----------
 rolling_mean.go    | 11 +++++++++++
 2 files changed, 11 insertions(+), 10 deletions(-)
 create mode 100644 rolling_mean.go

diff --git a/generic_rolling.go b/generic_rolling.go
index 1859108..80d2653 100644
--- a/generic_rolling.go
+++ b/generic_rolling.go
@@ -54,13 +54,3 @@ func (r RollingAndExpandingMixin) getBlocks() (blocks []Series) {
 
 	return
 }
-
-// Mean returns the rolling mean.
-func (r RollingAndExpandingMixin) Mean() (s Series) {
-	var d []float64
-	for _, block := range r.getBlocks() {
-		d = append(d, block.Mean())
-	}
-	s = NewSeries(SERIES_TYPE_FLOAT, r.series.Name(), d)
-	return
-}
diff --git a/rolling_mean.go b/rolling_mean.go
new file mode 100644
index 0000000..62dcf2c
--- /dev/null
+++ b/rolling_mean.go
@@ -0,0 +1,11 @@
+package pandas
+
+// Mean returns the rolling mean.
+func (r RollingAndExpandingMixin) Mean() (s Series) {
+	var d []float64
+	for _, block := range r.getBlocks() {
+		d = append(d, block.Mean())
+	}
+	s = NewSeries(SERIES_TYPE_FLOAT, r.series.Name(), d)
+	return
+}
-- 
Gitee


From 45769cd2db5f2f086a09f11091a652b669e8c5b9 Mon Sep 17 00:00:00 2001
From: wangfeng <wangfengxy@sina.cn>
Date: Sat, 4 Feb 2023 19:39:34 +0800
Subject: [PATCH 2/2] =?UTF-8?q?#I6CC1K=20=E5=AE=9E=E7=8E=B0DIFF=E5=8A=9F?=
 =?UTF-8?q?=E8=83=BD,=20=E5=8C=85=E6=8B=AC=E5=9B=BA=E5=AE=9A=E5=8F=82?=
 =?UTF-8?q?=E6=95=B0=E5=92=8C=E5=BA=8F=E5=88=97=E5=8C=96=E5=8F=82=E6=95=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 generic_diff.go      | 69 ++++++++++++++++++++++++++++++++++++++++++++
 generic_diff_test.go | 24 +++++++++++++++
 series.go            |  2 ++
 3 files changed, 95 insertions(+)
 create mode 100644 generic_diff.go
 create mode 100644 generic_diff_test.go

diff --git a/generic_diff.go b/generic_diff.go
new file mode 100644
index 0000000..9cc1a16
--- /dev/null
+++ b/generic_diff.go
@@ -0,0 +1,69 @@
+package pandas
+
+import (
+	"gitee.com/quant1x/pandas/stat"
+	"reflect"
+)
+
+//func (self *NDFrame) Diff_() float64 {
+//	if self.Len() < 1 {
+//		return NaN()
+//	}
+//	fs := make([]float64, 0)
+//	self.Apply(func(idx int, v any) {
+//		f := AnyToFloat64(v)
+//		fs = append(fs, f)
+//	})
+//	stdDev := avx2.Mean(fs)
+//	return stdDev
+//}
+
+// Diff 元素的第一个离散差
+// First discrete difference of element.
+// Calculates the difference of a {klass} element compared with another
+// element in the {klass} (default is element in previous row).
+func (self *NDFrame) Diff(param any) (s Series) {
+	if !(self.type_ == SERIES_TYPE_INT || self.type_ == SERIES_TYPE_FLOAT) {
+		return NewSeries(SERIES_TYPE_INVAILD, "", "")
+	}
+	var N []float32
+	switch v := param.(type) {
+	case int:
+		N = stat.Repeat[float32](float32(v), self.Len())
+	case Series:
+		vs := v.Values()
+		N = sliceToFloat32(vs)
+		N = stat.Align(N, Nil2Float32, self.Len())
+	default:
+		//periods = 1
+		N = stat.Repeat[float32](float32(1), self.Len())
+	}
+	r := RollingAndExpandingMixin{
+		window: N,
+		series: self,
+	}
+	var d []float64
+	var front = Nil2Float64
+	for _, block := range r.getBlocks() {
+		vs := reflect.ValueOf(block.Values())
+		vl := vs.Len()
+		if vl == 0 {
+			d = append(d, Nil2Float64)
+			continue
+		}
+		vf := vs.Index(0).Interface()
+		vc := vs.Index(vl - 1).Interface()
+		cu := AnyToFloat64(vc)
+		cf := AnyToFloat64(vf)
+		if Float64IsNaN(cu) || Float64IsNaN(front) {
+			front = cf
+			d = append(d, Nil2Float64)
+			continue
+		}
+		diff := cu - front
+		d = append(d, diff)
+		front = cf
+	}
+	s = NewSeries(SERIES_TYPE_FLOAT, r.series.Name(), d)
+	return
+}
diff --git a/generic_diff_test.go b/generic_diff_test.go
new file mode 100644
index 0000000..deff2d7
--- /dev/null
+++ b/generic_diff_test.go
@@ -0,0 +1,24 @@
+package pandas
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestNDFrame_Diff(t *testing.T) {
+	d1 := []float64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}
+	s1 := NewNDFrame[float64]("x", d1...)
+	df := NewDataFrame(s1)
+	fmt.Println(df)
+	fmt.Println("------------------------------------------------------------")
+	N := 2
+	fmt.Println("固定的参数, N =", N)
+	r1 := df.Col("x").Diff(N).Values()
+	fmt.Println("序列化结果:", r1)
+	fmt.Println("------------------------------------------------------------")
+	d2 := []float64{1, 2, 3, 4, 3, 3, 2, 1, Nil2Float64, Nil2Float64, Nil2Float64, Nil2Float64}
+	s2 := NewSeries(SERIES_TYPE_FLOAT, "x", d2)
+	fmt.Printf("序列化参数: %+v\n", s2.Values())
+	r2 := df.Col("x").Diff(s2).Values()
+	fmt.Println("序列化结果:", r2)
+}
diff --git a/series.go b/series.go
index 618cf8f..eadad4a 100644
--- a/series.go
+++ b/series.go
@@ -77,6 +77,8 @@ type Series interface {
 	Append(values ...interface{})
 	// Apply 接受一个回调函数
 	Apply(f func(idx int, v any))
+	// Diff 元素的第一个离散差
+	Diff(param any) (s Series)
 }
 
 // NewSeries 指定类型创建序列
-- 
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