GO语言基础之基础类型转换

func intToInt32() {
	var intNum int = 123
	int32Num := int32(intNum)
	fmt.Printf("int32Num type:%T,value: %v\n", int32Num, int32Num)
}

func int32ToUint() {
	var int32Num int32 = 456
	uintNum := uint(int32Num)
	fmt.Printf("uintNum type:%T,value: %v\n", uintNum, uintNum)
}

func intToString() {
	var intNum int = 789
	str := strconv.Itoa(intNum)
	fmt.Printf("str type:%T,value:%v\n", str, str)
	// itoa方法的实现源码如下：
	formatStr := strconv.FormatInt(int64(intNum), 10)
	fmt.Printf("formatStr type:%T,value:%v\n", formatStr, formatStr)
	// fmt的方式
	fmtstr := fmt.Sprint(intNum)
	fmt.Printf("fmtstr type:%T,value:%+v\n", fmtstr, fmtstr)
}

func stringToInt() {
	var str string = "124"
	num, _ := strconv.Atoi(str)
	fmt.Printf("num type:%T,value:%v\n", num, num)
	// atoi方法的实现源码如下：
	parseInt, _ := strconv.ParseInt(str, 10, 0)
	fmt.Printf("parseInt type:%T,value:%v\n", parseInt, parseInt)
}

func stringToIntErr() {
	var str string = "qwe"
	num, _ := strconv.Atoi(str)
	fmt.Printf("num type:%T,value:%v\n", num, num)
}

func byteToInt() {
	// 字符需要使用单引号包起来
	b := []byte{'1', '2', '3'}
	bytesBuffer := bytes.NewBuffer(b)
	fmt.Printf("bytesBuffer type:%T,value:%v\n", bytesBuffer, bytesBuffer)
	str := bytesBuffer.String()     // 先转为string
	byteNum, _ := strconv.Atoi(str) // 在转为int
	fmt.Printf("byteNum type:%T,value:%v\n", byteNum, byteNum)
}

func byteToInt32() {
	c := []byte{0, 0, 0, 99}
	cBytes := bytes.NewBuffer(c)
	var num int32
	binary.Read(cBytes, binary.BigEndian, &num)
	fmt.Printf("num type:%T,value:%v\n", num, num)
	// 0x表示16进制
	// 0x03转化二进制为0011，十进制为3，但是在第二节所以表示256*3=768
	// 0xe8转化二进制为1110 1000，十进制为232
	b := []byte{0x00, 0x00, 0x03, 0xe8}
	bBytes := bytes.NewBuffer(b)
	binary.Read(bBytes, binary.BigEndian, &num)
	fmt.Printf("num type:%T,value:%v\n", num, num)
}

func intToByte() {
	var num int32 = 99
	bytesBuffer := bytes.NewBuffer([]byte{})
	binary.Write(bytesBuffer, binary.BigEndian, num)
	byteB := bytesBuffer.Bytes()
	fmt.Printf("byteB type:%T,value:%v\n\n", byteB, byteB)
}

func byteToString() {
	buf := []byte{'h', 'e', 'l', 'l', 'o'}
	buf2 := bytes.NewBuffer(buf).String()
	fmt.Printf("buf2 type:%T,value:%v\n", buf2, buf2)
	// ascii值：48-57表示0-9，65-90表示A-Z,97-122表示a-z
	str := string([]byte{97, 98, 99, 100})
	fmt.Printf("str type:%T,value:%v\n\n", str, str)
}

func stringToByte() {
	// ascii值：48-57表示0-9，65-90表示A-Z,97-122表示a-z
	var str string = "hello"
	var bstr []byte = []byte(str)
	fmt.Printf("bstr: type:%T,value:%v\n", bstr, bstr)
}