The constants and operators of the Go language

Use Case 1

//此文件用来练习//常量与运算符的package mainimport "fmt"//定义单个常量const SPARK_NAME = "spark-test001"const NODE_NUM int = 3//下面的方式，只是简写const (    CPU    = 3.4    MEMORY = 1024)//同时定义多个变量const FTP_NAME, ES_NAME, YARN_NAME = "ftp-beijing", "es-beijing", "yarn-shanghai"const (    ftp_cpu, es_cpu, yarn_cpu = 3.4, 5.6, 8.9)func main() {    fmt.Println("spark_name:\t", SPARK_NAME)    fmt.Println("node_num:\t", NODE_NUM)    fmt.Println("cpu:\t",CPU)    fmt.Println("ftp_name:\t", FTP_NAME)    fmt.Println("es_name:\t", ES_NAME)    fmt.Println("yarn_name:\t",YARN_NAME)    fmt.Println("ftp_cpu:\t",ftp_cpu)    fmt.Println("es_cpu:\t", es_cpu)    fmt.Println("yarn_cpu:\t", yarn_cpu)}

Use Case 2

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    a = "A"    //定义常量组时，如果不提供初始化值的话，则表示将使用上行的表达式    //因此，b,d,d的值全是A    b    c    d)func main() {    fmt.Println(a)    fmt.Println(b)    fmt.Println(c)    fmt.Println(d)}

Enumeration Example 1

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    z = "A"    //iota是常量的计数器，从0开始，组中每定义1个常量自动递增1    //通过初始化规则与iota可以达到枚举的效果    //每遇到一个const关键字，iota就会重置为0    b = iota    c    d)func main() {    fmt.Println(z)    fmt.Println(b) //1    fmt.Println(c) //2    fmt.Println(d) //3}

Example 2

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    z = "A"    b = iota    c = iota    d)func main() {    fmt.Println(z)    fmt.Println(b) //1    fmt.Println(c) //2    fmt.Println(d) //3}

Example 3

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    //第一个常量不可省略表达式    Monday    = iota    Tuesday    Wednesday    Thursday    Friday    Saturday    Sunday)func main() {    fmt.Println(Monday)    //0    fmt.Println(Tuesday)   //1    fmt.Println(Wednesday) //2    fmt.Println(Thursday)  //3    fmt.Println(Friday)    //4    fmt.Println(Saturday)  //5    fmt.Println(Sunday)    //6}

Example 4

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    //第一个常量不可省略表达式    Monday    = iota    Tuesday    Wednesday = "we"    Thursday = iota    Friday  = "go"    Saturday = iota    Sunday)func main() {    fmt.Println(Monday)    //0    fmt.Println(Tuesday)   //1    fmt.Println(Wednesday) //we    fmt.Println(Thursday)  //3    fmt.Println(Friday)    //go    fmt.Println(Saturday)  //5    fmt.Println(Sunday)    //6}

Example 4

//此文件用来练习//常量与运算符的package mainimport "fmt"const (    Monday    = "spark"    Tuesday   = "hadoop"    Wednesday = "k8s"    Thursday = iota    Friday    Saturday    Sunday)func main() {    fmt.Println(Monday)    //spark    fmt.Println(Tuesday)   //hadoop    fmt.Println(Wednesday) //k8s    fmt.Println(Thursday)  //3    fmt.Println(Friday)    //4    fmt.Println(Saturday)  //5    fmt.Println(Sunday)    //6}

Operators in the Go language

Shift operator 1, left shift right shift test

//此文件用来练习//常量与运算符的package mainimport "fmt"func main() {    //移位运算符测试    fmt.Println(1 << 1)              //2    fmt.Println(1 << 2)              //4    fmt.Println(1 << 4)              //16    fmt.Println(1 << 10)             //1024    fmt.Println(1 << 10 << 10)       //1048576    fmt.Println(1 << 10 << 10 >> 10) //1024}

2, bitwise operators

A&^b indicates that if a position of B is 1, force the element on a of the corresponding position to be cast to 0

&& The good thing is that after the first failure, there is no subsequent judgment.

Enumeration of computer storage units with constants iota and << operators

//此文件用来练习//目的:结合常量iota与<< 运算符实现计算机存储单位的枚举// byte, KB,MB,GB,TB,PB等等package mainimport "fmt"const(    byte float64 = 1 << (iota * 10)    //说明：    //下面的常量，并没有初始化，就会默认采用上面的表达式    // KB = 1 << (iota * 10)， 只是，iota 再不断的增加    KB    MB    GB)func main() {    fmt.Println(byte)    fmt.Println(KB)    fmt.Println(MB)    fmt.Println(GB)}

The constants and operators of the Go language