Reduce if statements in loops

Improved the use of `if` statements for the first column when outputting delimiters.
noborus · Aug 6, 2024 · 0b39c15 · 0b39c15
1 parent 79e3a38
commit 0b39c15
Show file tree

Hide file tree

Showing 3 changed files with 80 additions and 42 deletions.
diff --git a/output_csv.go b/output_csv.go
@@ -54,11 +54,16 @@ func (w *CSVWriter) PreWrite(columns []string, types []string) error {
 	if !w.outHeader {
 		return nil
 	}
-	for n, column := range columns {
-		if n > 0 {
-			if _, err := w.writer.WriteRune(w.outDelimiter); err != nil {
-				return err
-			}
+	if len(columns) == 0 {
+		return nil
+	}
+	if err := w.writeColumnString(columns[0]); err != nil {
+		return err
+	}
+
+	for _, column := range columns[1:] {
+		if _, err := w.writer.WriteRune(w.outDelimiter); err != nil {
+			return err
 		}
 		if err := w.writeColumnString(column); err != nil {
 			return err
@@ -70,11 +75,17 @@ func (w *CSVWriter) PreWrite(columns []string, types []string) error {
 
 // WriteRow is row write.
 func (w *CSVWriter) WriteRow(values []any, _ []string) error {
-	for n, column := range values {
-		if n > 0 {
-			if _, err := w.writer.WriteRune(w.outDelimiter); err != nil {
-				return err
-			}
+	if len(values) == 0 {
+		_, err := w.writer.WriteString(w.endLine)
+		return err
+	}
+
+	if err := w.writeColumn(values[0]); err != nil {
+		return err
+	}
+	for _, column := range values[1:] {
+		if _, err := w.writer.WriteRune(w.outDelimiter); err != nil {
+			return err
 		}
 		if err := w.writeColumn(column); err != nil {
 			return err

diff --git a/output_ltsv.go b/output_ltsv.go
@@ -31,30 +31,41 @@ func (w *LTSVWriter) PreWrite(columns []string, types []string) error {
 
 // WriteRow is row write to LTSV.
 func (w *LTSVWriter) WriteRow(values []any, labels []string) error {
-	for n, col := range values {
-		if n > 0 {
-			if _, err := w.writer.WriteRune(w.delimiter); err != nil {
-				return err
-			}
-		}
-		if _, err := w.writer.WriteString(labels[n]); err != nil {
-			return err
-		}
-		if err := w.writer.WriteByte(':'); err != nil {
+	if len(values) == 0 {
+		return nil
+	}
+	if err := w.writeColumn(labels[0], values[0]); err != nil {
+		return err
+	}
+	for n, col := range values[1:] {
+		if _, err := w.writer.WriteRune(w.delimiter); err != nil {
 			return err
 		}
-
-		str := ValString(col)
-		if col == nil && w.needNULL {
-			str = w.outNULL
-		}
-		if _, err := w.writer.WriteString(str); err != nil {
+		if err := w.writeColumn(labels[n+1], col); err != nil {
 			return err
 		}
 	}
 	return w.writer.WriteByte('\n')
 }
 
+func (w *LTSVWriter) writeColumn(label string, value any) error {
+	if _, err := w.writer.WriteString(label); err != nil {
+		return err
+	}
+	if err := w.writer.WriteByte(':'); err != nil {
+		return err
+	}
+
+	str := ValString(value)
+	if value == nil && w.needNULL {
+		str = w.outNULL
+	}
+	if _, err := w.writer.WriteString(str); err != nil {
+		return err
+	}
+	return nil
+}
+
 // PostWrite is flush.
 func (w *LTSVWriter) PostWrite() error {
 	return w.writer.Flush()

diff --git a/output_raw.go b/output_raw.go
@@ -40,13 +40,17 @@ func (w *RAWWriter) PreWrite(columns []string, types []string) error {
 	if !w.outHeader {
 		return nil
 	}
-	for n, col := range columns {
-		if n > 0 {
-			if _, err := w.writer.WriteString(w.delimiter); err != nil {
-				return err
-			}
+	if len(columns) == 0 {
+		return nil
+	}
+	if err := w.writeColumn(columns[0]); err != nil {
+		return err
+	}
+	for _, col := range columns[1:] {
+		if _, err := w.writer.WriteString(w.delimiter); err != nil {
+			return err
 		}
-		if _, err := w.writer.WriteString(col); err != nil {
+		if err := w.writeColumn(col); err != nil {
 			return err
 		}
 	}
@@ -56,23 +60,35 @@ func (w *RAWWriter) PreWrite(columns []string, types []string) error {
 
 // WriteRow is row write.
 func (w *RAWWriter) WriteRow(values []any, _ []string) error {
-	for n, col := range values {
-		if n > 0 {
-			if _, err := w.writer.WriteString(w.delimiter); err != nil {
-				return err
-			}
-		}
-		str := ValString(col)
-		if col == nil && w.needNULL {
-			str = w.outNULL
+	if len(values) == 0 {
+		return nil
+	}
+	if err := w.writeColumn(values[0]); err != nil {
+		return err
+	}
+	for _, col := range values[1:] {
+		if _, err := w.writer.WriteString(w.delimiter); err != nil {
+			return err
 		}
-		if _, err := w.writer.WriteString(str); err != nil {
+
+		if err := w.writeColumn(col); err != nil {
 			return err
 		}
 	}
 	return w.writer.WriteByte('\n')
 }
 
+func (w *RAWWriter) writeColumn(value any) error {
+	str := ValString(value)
+	if value == nil && w.needNULL {
+		str = w.outNULL
+	}
+	if _, err := w.writer.WriteString(str); err != nil {
+		return err
+	}
+	return nil
+}
+
 // PostWrite is flush.
 func (w *RAWWriter) PostWrite() error {
 	return w.writer.Flush()