diff --git a/cell.go b/cell.go
index c47b1f1..36b8ef9 100644
--- a/cell.go
+++ b/cell.go
@@ -91,11 +91,11 @@ func (f *File) GetCellValue(sheet, axis string) string {
 	if rows < xAxis {
 		return ""
 	}
-	for _, v := range xlsx.SheetData.Row {
-		if v.R == row {
-			for _, r := range v.C {
-				if axis == r.R {
-					val, _ := r.getValueFrom(f, f.sharedStringsReader())
+	for k := range xlsx.SheetData.Row {
+		if xlsx.SheetData.Row[k].R == row {
+			for i := range xlsx.SheetData.Row[k].C {
+				if axis == xlsx.SheetData.Row[k].C[i].R {
+					val, _ := xlsx.SheetData.Row[k].C[i].getValueFrom(f, f.sharedStringsReader())
 					return val
 				}
 			}
@@ -161,12 +161,12 @@ func (f *File) GetCellFormula(sheet, axis string) string {
 	if rows < xAxis {
 		return ""
 	}
-	for _, v := range xlsx.SheetData.Row {
-		if v.R == row {
-			for _, f := range v.C {
-				if axis == f.R {
-					if f.F != nil {
-						return f.F.Content
+	for k := range xlsx.SheetData.Row {
+		if xlsx.SheetData.Row[k].R == row {
+			for i := range xlsx.SheetData.Row[k].C {
+				if axis == xlsx.SheetData.Row[k].C[i].R {
+					if xlsx.SheetData.Row[k].C[i].F != nil {
+						return xlsx.SheetData.Row[k].C[i].F.Content
 					}
 				}
 			}
@@ -256,12 +256,12 @@ func (f *File) GetCellHyperLink(sheet, axis string) (bool, string) {
 	if xlsx.Hyperlinks == nil || axis == "" {
 		return link, target
 	}
-	for _, h := range xlsx.Hyperlinks.Hyperlink {
-		if h.Ref == axis {
+	for h := range xlsx.Hyperlinks.Hyperlink {
+		if xlsx.Hyperlinks.Hyperlink[h].Ref == axis {
 			link = true
-			target = h.Location
-			if h.RID != "" {
-				target = f.getSheetRelationshipsTargetByID(sheet, h.RID)
+			target = xlsx.Hyperlinks.Hyperlink[h].Location
+			if xlsx.Hyperlinks.Hyperlink[h].RID != "" {
+				target = f.getSheetRelationshipsTargetByID(sheet, xlsx.Hyperlinks.Hyperlink[h].RID)
 			}
 		}
 	}
diff --git a/chart.go b/chart.go
index f36c83a..e6cb94f 100644
--- a/chart.go
+++ b/chart.go
@@ -550,23 +550,23 @@ func (f *File) drawScatterChart(formatSet *formatChart) *cPlotArea {
 // sets.
 func (f *File) drawChartSeries(formatSet *formatChart) *[]cSer {
 	ser := []cSer{}
-	for k, v := range formatSet.Series {
+	for k := range formatSet.Series {
 		ser = append(ser, cSer{
 			IDx:   &attrValInt{Val: k},
 			Order: &attrValInt{Val: k},
 			Tx: &cTx{
 				StrRef: &cStrRef{
-					F: v.Name,
+					F: formatSet.Series[k].Name,
 				},
 			},
 			SpPr:   f.drawChartSeriesSpPr(k, formatSet),
 			Marker: f.drawChartSeriesMarker(k, formatSet),
 			DPt:    f.drawChartSeriesDPt(k, formatSet),
 			DLbls:  f.drawChartSeriesDLbls(formatSet),
-			Cat:    f.drawChartSeriesCat(v, formatSet),
-			Val:    f.drawChartSeriesVal(v, formatSet),
-			XVal:   f.drawChartSeriesXVal(v, formatSet),
-			YVal:   f.drawChartSeriesYVal(v, formatSet),
+			Cat:    f.drawChartSeriesCat(formatSet.Series[k], formatSet),
+			Val:    f.drawChartSeriesVal(formatSet.Series[k], formatSet),
+			XVal:   f.drawChartSeriesXVal(formatSet.Series[k], formatSet),
+			YVal:   f.drawChartSeriesYVal(formatSet.Series[k], formatSet),
 		})
 	}
 	return &ser
diff --git a/col.go b/col.go
index d9c4390..cc064c4 100644
--- a/col.go
+++ b/col.go
@@ -27,9 +27,9 @@ func (f *File) GetColVisible(sheet, column string) bool {
 	if xlsx.Cols == nil {
 		return visible
 	}
-	for _, c := range xlsx.Cols.Col {
-		if c.Min <= col && col <= c.Max {
-			visible = !c.Hidden
+	for c := range xlsx.Cols.Col {
+		if xlsx.Cols.Col[c].Min <= col && col <= xlsx.Cols.Col[c].Max {
+			visible = !xlsx.Cols.Col[c].Hidden
 		}
 	}
 	return visible
@@ -55,9 +55,9 @@ func (f *File) SetColVisible(sheet, column string, visible bool) {
 		xlsx.Cols = &cols
 		return
 	}
-	for _, v := range xlsx.Cols.Col {
-		if v.Min <= c && c <= v.Max {
-			col = v
+	for v := range xlsx.Cols.Col {
+		if xlsx.Cols.Col[v].Min <= c && c <= xlsx.Cols.Col[v].Max {
+			col = xlsx.Cols.Col[v]
 		}
 	}
 	col.Min = c
@@ -262,12 +262,12 @@ func (f *File) InsertCol(sheet, column string) {
 //
 func (f *File) RemoveCol(sheet, column string) {
 	xlsx := f.workSheetReader(sheet)
-	for i, r := range xlsx.SheetData.Row {
-		for k, v := range r.C {
+	for r := range xlsx.SheetData.Row {
+		for k, v := range xlsx.SheetData.Row[r].C {
 			axis := v.R
 			col := string(strings.Map(letterOnlyMapF, axis))
 			if col == column {
-				xlsx.SheetData.Row[i].C = append(xlsx.SheetData.Row[i].C[:k], xlsx.SheetData.Row[i].C[k+1:]...)
+				xlsx.SheetData.Row[r].C = append(xlsx.SheetData.Row[r].C[:k], xlsx.SheetData.Row[r].C[k+1:]...)
 			}
 		}
 	}
@@ -278,13 +278,13 @@ func (f *File) RemoveCol(sheet, column string) {
 // Completion column element tags of XML in a sheet.
 func completeCol(xlsx *xlsxWorksheet, row, cell int) {
 	buffer := bytes.Buffer{}
-	for k, v := range xlsx.SheetData.Row {
-		if len(v.C) < cell {
-			start := len(v.C)
+	for r := range xlsx.SheetData.Row {
+		if len(xlsx.SheetData.Row[r].C) < cell {
+			start := len(xlsx.SheetData.Row[r].C)
 			for iii := start; iii < cell; iii++ {
 				buffer.WriteString(ToAlphaString(iii))
-				buffer.WriteString(strconv.Itoa(k + 1))
-				xlsx.SheetData.Row[k].C = append(xlsx.SheetData.Row[k].C, xlsxC{
+				buffer.WriteString(strconv.Itoa(r + 1))
+				xlsx.SheetData.Row[r].C = append(xlsx.SheetData.Row[r].C, xlsxC{
 					R: buffer.String(),
 				})
 				buffer.Reset()
diff --git a/excelize.go b/excelize.go
index e3b5dac..95bce34 100644
--- a/excelize.go
+++ b/excelize.go
@@ -113,8 +113,8 @@ func checkSheet(xlsx *xlsxWorksheet) {
 	}
 	sheetData := xlsxSheetData{}
 	existsRows := map[int]int{}
-	for k, v := range xlsx.SheetData.Row {
-		existsRows[v.R] = k
+	for k := range xlsx.SheetData.Row {
+		existsRows[xlsx.SheetData.Row[k].R] = k
 	}
 	for i := 0; i < row; i++ {
 		_, ok := existsRows[i+1]
@@ -167,8 +167,8 @@ func replaceWorkSheetsRelationshipsNameSpace(workbookMarshal string) string {
 func (f *File) UpdateLinkedValue() {
 	for _, name := range f.GetSheetMap() {
 		xlsx := f.workSheetReader(name)
-		for indexR, row := range xlsx.SheetData.Row {
-			for indexC, col := range row.C {
+		for indexR := range xlsx.SheetData.Row {
+			for indexC, col := range xlsx.SheetData.Row[indexR].C {
 				if col.F != nil && col.V != "" {
 					xlsx.SheetData.Row[indexR].C[indexC].V = ""
 					xlsx.SheetData.Row[indexR].C[indexC].T = ""
diff --git a/rows.go b/rows.go
index 9bbbec2..78ed664 100644
--- a/rows.go
+++ b/rows.go
@@ -266,11 +266,11 @@ func (f *File) InsertRow(sheet string, row int) {
 // 3000 rows one sheet).
 func checkRow(xlsx *xlsxWorksheet) {
 	buffer := bytes.Buffer{}
-	for k, v := range xlsx.SheetData.Row {
-		lenCol := len(v.C)
+	for k := range xlsx.SheetData.Row {
+		lenCol := len(xlsx.SheetData.Row[k].C)
 		if lenCol > 0 {
-			endR := string(strings.Map(letterOnlyMapF, v.C[lenCol-1].R))
-			endRow, _ := strconv.Atoi(strings.Map(intOnlyMapF, v.C[lenCol-1].R))
+			endR := string(strings.Map(letterOnlyMapF, xlsx.SheetData.Row[k].C[lenCol-1].R))
+			endRow, _ := strconv.Atoi(strings.Map(intOnlyMapF, xlsx.SheetData.Row[k].C[lenCol-1].R))
 			endCol := TitleToNumber(endR) + 1
 			if lenCol < endCol {
 				oldRow := xlsx.SheetData.Row[k].C