go學習(9)string字串函式
阿新 • • 發佈:2018-12-12
常用字串操作函式
型別轉換
比較對比
搜尋 查詢 統計
替換
刪除過濾
大小寫轉換
字首字尾
字串分割
拼接
中拼接字串方式對比
package main import ( "bytes" "fmt" "strconv" "strings" "time" ) func main() { fmt.Println("字串測試") fmt.Println("字串轉化") //獲取程式執行的作業系統平臺下 int 型別所佔的位數,如:strconv.IntSize。 //strconv.IntSize fmt.Println("將字串轉換為 int 型。") var trastr01 string = "100" traint01, err_tra := strconv.Atoi(trastr01) if err_tra != nil { fmt.Println(err_tra) } else { fmt.Println(traint01) } fmt.Println("將字串轉換為 float64 型") var trastr02 string = "100.55" trafloat01, err_float := strconv.ParseFloat(trastr02, 10) if err_float != nil { fmt.Println(err_float) } else { fmt.Println(trafloat01) } trastr03 := strconv.Itoa(99) fmt.Println("int 轉字元安 " + trastr03) var str01 string = "hello,world" str02 := "你好,世界" fmt.Println(str01) fmt.Println(str02) //字串比較 com01 := strings.Compare(str01, str02) if com01 == 0 { fmt.Println("相等") } else { fmt.Println("不相等 " + string(com01)) } fmt.Println(com01) //查詢 包含 var isCon bool = strings.Contains(str01, "hello") fmt.Println(isCon) //true //查詢位置 var theIndex int = strings.Index(str01, ",") fmt.Println(theIndex) //5 fmt.Println(strings.Index(str01, "haha")) //不存在返回-1 lastIndex := strings.LastIndex(str01, "o") fmt.Println("在字串中最後出現位置的索引 " + strconv.Itoa(lastIndex)) //7 //-1 表示字串 s 不包含字串 //統計給定子串sep的出現次數, sep為空時, 返回1 + 字串的長度 fmt.Println(strings.Count("cheeseeee", "ee")) // 3 fmt.Println(strings.Count("five", "")) // 5 // 重複s字串count次, 最後返回新生成的重複的字串 fmt.Println("hello " + strings.Repeat("world ", 10)) fmt.Println("替換") // 在s字串中, 把old字串替換為new字串,n表示替換的次數,小於0表示全部替換 var str03 string = "/Users//Documents/GOPatch/src/MyGO/config/TestString/" str04 := strings.Replace(str03, "/", "**", -1) str05 := strings.Replace(str03, "/", "**", 4) fmt.Println(str04) //**Users****Documents**GOPatch**src**MyGO**config**TestString** fmt.Println(str05) //**Users****Documents**GOPatch/src/MyGO/config/TestString/ fmt.Println("刪除字串的開頭和尾部") fmt.Println("刪除兩頭的/ = " + strings.Trim(str03, "/")) //Users//Documents/GOPatch/src/MyGO/config/TestString fmt.Println("刪除左邊的/ = " + strings.TrimLeft(str03, "/")) //Users//Documents/GOPatch/src/MyGO/config/TestString/ //還有 TrimRight str06 := strings.TrimSpace(" hello hao hao hao ") fmt.Println("刪除開頭末尾的空格 =" + str06) //'hello hao hao hao' fmt.Println("大小寫") str07 := "hello hao hao hao" fmt.Println(strings.Title(str07)) //Hello Hao Hao Hao fmt.Println(strings.ToLower(" Hello Hao Hao Hao")) // hello hao hao hao fmt.Println(strings.ToUpper(str07)) //HELLO HAO HAO HAO //字首 字尾 fmt.Println(strings.HasPrefix("Gopher", "Go")) // true fmt.Println(strings.HasSuffix("Amigo", "go")) // true fmt.Println("字串分割") fieldsStr := " hello it's a nice day today " //根據空白符分割,不限定中間間隔幾個空白符 fieldsSlece := strings.Fields(fieldsStr) fmt.Println(fieldsSlece) //[hello it's a nice day today] for i, v := range fieldsSlece { fmt.Printf("下標 %d 對應值 = %s \n", i, v) } for i := 0; i < len(fieldsSlece); i++ { fmt.Println(fieldsSlece[i]) } //根據特定字元分割 slice01 := strings.Split("q,w,e,r,t,y,", ",") fmt.Println(slice01) //[q w e r t y ] fmt.Println(cap(slice01)) //7 最後多個空"" for i, v := range slice01 { fmt.Printf("下標 %d 對應值 = %s \n", i, v) } //拼接 //Join 用於將元素型別為 string 的 slice, 使用分割符號來拼接組成一個字串: var str08 string = strings.Join(fieldsSlece, ",") fmt.Println("Join拼接結果=" + str08) //hello,it's,a,nice,day,today fmt.Println("------------對比字串拼接效率----------------") var buffer bytes.Buffer start := time.Now() for i := 0; i < 100000; i++ { buffer.WriteString("test is here\n") } buffer.String() // 拼接結果 end := time.Now() fmt.Println("Buffer time is ", end.Sub(start).Seconds()) start = time.Now() str := "" for i := 0; i < 100000; i++ { str += "test is here\n" } end = time.Now() fmt.Println("+= time is ", end.Sub(start).Seconds()) start = time.Now() var sl []string for i := 0; i < 100000; i++ { sl = append(sl, "test is here\n") } strings.Join(sl, "") end = time.Now() fmt.Println("Join time is", end.Sub(start).Seconds()) /* Buffer time is 0.00388283 += time is 11.730007558 Join time is 0.016644653 */ }