From ca3c998ccca81e3666dd3dd73c70fdc33e71cfc1 Mon Sep 17 00:00:00 2001
From: hau <ngtranhau@gmail.com>
Date: Sun, 6 Sep 2020 16:35:58 +0700
Subject: [PATCH] add new concat

---
 Development/Go/strings.md | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Development/Go/strings.md b/Development/Go/strings.md
index 57af105..23b134c 100644
--- a/Development/Go/strings.md
+++ b/Development/Go/strings.md
@@ -7,3 +7,23 @@ template := "My city is {city} and my country is {country}"
 r := strings.NewReplacer("{city}", "Sai Gon", "{country}", "Viet Nam")
 fmt.Println(r.Replace(template))
 ```
+
+Use `Builder` to **efficently** concat string:
+
+```go
+func oldConcat(strs ...string) string {
+	var result string
+	for _, str := range strs {
+		result += str
+	}
+	return result
+}
+
+func newConcat(strs ...string) string {
+	var sb strings.Builder
+	for _, str := range strs {
+		sb.WriteString(str)
+	}
+	return sb.String()
+}
+```