diff --git a/formatter/formatter.go b/formatter/formatter.go
index 8219430..e7fb426 100644
--- a/formatter/formatter.go
+++ b/formatter/formatter.go
@@ -8,41 +8,36 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"math"
+	"strconv"
+	"strings"
+	"unicode"
 
 	"github.com/duke-git/lancet/convertor"
-	"github.com/duke-git/lancet/strutil"
-	"github.com/duke-git/lancet/validator"
 )
 
 // Comma add comma to a number value by every 3 numbers from right. ahead by symbol char.
 // if value is invalid number string eg "aa", return empty string
 // Comma("12345", "$") => "$12,345", Comma(12345, "$") => "$12,345"
 func Comma(value interface{}, symbol string) string {
-	if validator.IsInt(value) {
-		v, err := convertor.ToInt(value)
-		if err != nil {
-			return ""
-		}
-		return symbol + commaInt(v)
-	}
+	numString := convertor.ToString(value)
 
-	if validator.IsFloat(value) {
-		v, err := convertor.ToFloat(value)
-		if err != nil {
-			return ""
-		}
-		return symbol + commaFloat(v)
-	}
-
-	if strutil.IsString(value) {
-		v := fmt.Sprintf("%v", value)
-		if validator.IsNumberStr(v) {
-			return symbol + commaStr(v)
-		}
+	_, err := strconv.ParseFloat(numString, 64)
+	if err != nil {
 		return ""
 	}
 
-	return ""
+	index := strings.Index(numString, ".")
+	if index == -1 {
+		index = len(numString)
+	}
+
+	for index > 3 {
+		index = index - 3
+		numString = numString[:index] + "," + numString[index:]
+	}
+
+	return symbol + numString
 }
 
 // Pretty data to JSON string.
@@ -177,3 +172,50 @@ func ParseDecimalBytes(size string) (uint64, error) {
 func ParseBinaryBytes(size string) (uint64, error) {
 	return parseBytes(size, "binary")
 }
+
+// see https://github.com/dustin/go-humanize/blob/master/bytes.go
+func parseBytes(s string, kind string) (uint64, error) {
+	lastDigit := 0
+	hasComma := false
+	for _, r := range s {
+		if !(unicode.IsDigit(r) || r == '.' || r == ',') {
+			break
+		}
+		if r == ',' {
+			hasComma = true
+		}
+		lastDigit++
+	}
+
+	num := s[:lastDigit]
+	if hasComma {
+		num = strings.Replace(num, ",", "", -1)
+	}
+
+	f, err := strconv.ParseFloat(num, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	extra := strings.ToLower(strings.TrimSpace(s[lastDigit:]))
+
+	if kind == "decimal" {
+		if m, ok := decimalByteMap[extra]; ok {
+			f *= float64(m)
+			if f >= math.MaxUint64 {
+				return 0, fmt.Errorf("too large: %v", s)
+			}
+			return uint64(f), nil
+		}
+	} else {
+		if m, ok := binaryByteMap[extra]; ok {
+			f *= float64(m)
+			if f >= math.MaxUint64 {
+				return 0, fmt.Errorf("too large: %v", s)
+			}
+			return uint64(f), nil
+		}
+	}
+
+	return 0, fmt.Errorf("unhandled size name: %v", extra)
+}
diff --git a/formatter/formatter_internal.go b/formatter/formatter_internal.go
deleted file mode 100644
index 43427cc..0000000
--- a/formatter/formatter_internal.go
+++ /dev/null
@@ -1,134 +0,0 @@
-package formatter
-
-import (
-	"bytes"
-	"fmt"
-	"math"
-	"strconv"
-	"strings"
-	"unicode"
-)
-
-// see https://github.com/dustin/go-humanize/blob/master/comma.go
-func commaInt(v int64) string {
-	sign := ""
-
-	// Min int64 can't be negated to a usable value, so it has to be special cased.
-	if v == math.MinInt64 {
-		return "-9,223,372,036,854,775,808"
-	}
-
-	if v < 0 {
-		sign = "-"
-		v = 0 - v
-	}
-
-	parts := []string{"", "", "", "", "", "", ""}
-	j := len(parts) - 1
-
-	for v > 999 {
-		parts[j] = strconv.FormatInt(v%1000, 10)
-		switch len(parts[j]) {
-		case 2:
-			parts[j] = "0" + parts[j]
-		case 1:
-			parts[j] = "00" + parts[j]
-		}
-		v = v / 1000
-		j--
-	}
-	parts[j] = strconv.Itoa(int(v))
-	return sign + strings.Join(parts[j:], ",")
-}
-
-func commaFloat(v float64) string {
-	buf := &bytes.Buffer{}
-	if v < 0 {
-		buf.Write([]byte{'-'})
-		v = 0 - v
-	}
-
-	comma := []byte{','}
-
-	parts := strings.Split(strconv.FormatFloat(v, 'f', -1, 64), ".")
-	pos := 0
-	if len(parts[0])%3 != 0 {
-		pos += len(parts[0]) % 3
-		buf.WriteString(parts[0][:pos])
-		buf.Write(comma)
-	}
-	for ; pos < len(parts[0]); pos += 3 {
-		buf.WriteString(parts[0][pos : pos+3])
-		buf.Write(comma)
-	}
-	buf.Truncate(buf.Len() - 1)
-
-	if len(parts) > 1 {
-		buf.Write([]byte{'.'})
-		buf.WriteString(parts[1])
-	}
-	return buf.String()
-}
-
-func commaStr(s string) string {
-	dotIndex := strings.Index(s, ".")
-	if dotIndex != -1 {
-		return commaStrRecursive(s[:dotIndex]) + s[dotIndex:]
-	}
-
-	return commaStrRecursive(s)
-}
-
-func commaStrRecursive(s string) string {
-	if len(s) <= 3 {
-		return s
-	}
-	return commaStrRecursive(s[:len(s)-3]) + "," + commaStrRecursive(s[len(s)-3:])
-}
-
-// see https://github.com/dustin/go-humanize/blob/master/bytes.go
-func parseBytes(s string, kind string) (uint64, error) {
-	lastDigit := 0
-	hasComma := false
-	for _, r := range s {
-		if !(unicode.IsDigit(r) || r == '.' || r == ',') {
-			break
-		}
-		if r == ',' {
-			hasComma = true
-		}
-		lastDigit++
-	}
-
-	num := s[:lastDigit]
-	if hasComma {
-		num = strings.Replace(num, ",", "", -1)
-	}
-
-	f, err := strconv.ParseFloat(num, 64)
-	if err != nil {
-		return 0, err
-	}
-
-	extra := strings.ToLower(strings.TrimSpace(s[lastDigit:]))
-
-	if kind == "decimal" {
-		if m, ok := decimalByteMap[extra]; ok {
-			f *= float64(m)
-			if f >= math.MaxUint64 {
-				return 0, fmt.Errorf("too large: %v", s)
-			}
-			return uint64(f), nil
-		}
-	} else {
-		if m, ok := binaryByteMap[extra]; ok {
-			f *= float64(m)
-			if f >= math.MaxUint64 {
-				return 0, fmt.Errorf("too large: %v", s)
-			}
-			return uint64(f), nil
-		}
-	}
-
-	return 0, fmt.Errorf("unhandled size name: %v", extra)
-}