Update statistics.go (#287)

当在网页的文本框中输入中文逗号来分隔的数字和汉字或者数字和英文的组合时，错误信息打印不正确的问题

eBook/exercises/chapter_15/statistics.go

@@ -53,8 +53,14 @@ func homePage(writer http.ResponseWriter, request *http.Request) {
 
 func processRequest(request *http.Request) ([]float64, string, bool) {
     var numbers []float64
+    var text string
     if slice, found := request.Form["numbers"]; found && len(slice) > 0 {
-        text := strings.Replace(slice[0], ",", " ", -1)
+        //处理如果网页中输入的是中文逗号
+	if strings.Contains(slice[0], "&#65292") {
+	    text = strings.Replace(slice[0], "，", " ", -1)
+	} else {
+	    text = strings.Replace(slice[0], ",", " ", -1)
+	}
         for _, field := range strings.Fields(text) {
             if x, err := strconv.ParseFloat(field, 64); err != nil {
                 return numbers, "'" + field + "' is invalid", false