An article to help you understand the basic operators and flow control of Go language

This time we continue to learn the basic operators and process control of Go.

Operator

The name operator sounds mysterious, but in fact we see it a lot more often, like =, ,/some type of.

Operators are mainly divided into

• arithmetic operators

• Relational operators

• Logical operators

• Bit operator

• Assignment operator

The following is simple Learn about the following.

Arithmetic operators

##As the name suggests, arithmetic operators are mainly used in arithmetic, such as addition, subtraction, multiplication and division

Briefly understand the following.

Relational operators

Operator	##Description
	##Add
-	subtraction
*	Multiply
/	Division
#%	Look for remainder
	自add
##--	自decrement

##!= Check whether the two values ​​​​are not equal, return True if they are not equal, otherwise return False>Check whether the value on the left is greater than the value on the right, if so return True otherwise return False

Logical operators

##Operators	Description
##==	Check whether the two values ​​are equal, return True if they are equal, otherwise return False
>=	Check whether the value on the left is greater than or equal to the value on the right, if so Returns True otherwise returns False
##<	Check Whether the value on the left is less than the value on the right, if so return True otherwise return False
##<=	Check whether the value on the left is less than or equal to the value on the right, if so return True otherwise return False

##!Logical NOT operator. False if the condition is True, True otherwise

Note: Logical operators are very important and are often used in development.

Bit operators

Bit operators have some low-level functions and are used in special cases.

##Operators	describe
&&	Logical and operator. If both operands are True, it is True, otherwise it is False
##||	Logical or operator. If the operands on both sides have a True, it is True, otherwise it is False

##The two numbers involved in the operation correspond to Carry AND. (It is 1 if both are 1) |The binary OR corresponding to each of the two numbers involved in the operation. (If one of the two bits is 1, it is 1) ##^

Assignment Operator

The assignment operator is also commonly used in development.

Operator	##Description
##&
The corresponding binary bits of the two numbers participating in the operation are exclusive or. When the two corresponding binary bits are different, the result is 1.(If the two numbers are different, it is 1)
<<	##Shifting n bits to the left is multiplying by 2 raised to the nth power. "a<
##>>	Shift right by n bits That's divided by 2 to the nth power. "a>>b" shifts all binary bits of a to the right by b bits.

##*=##>>=Assign value after right shift&=|

Process control

In Go, there are the following types of process control.

• if

• ##if

• switch case

• for

• Standard for

• ##forrange

##goto(Use with caution )

##if

Syntax

//方式一,一个if
if 条件{
    //执行语句
}
//方式二,if条件不成功执行else
if 条件{
    //if成功语句
}else{
    //if不成功语句
}
//方式三,带有else if得
if 条件1{
    //if成功语句
}else if 条件2{
    //if不成功,继续else if条件
}else{
    //上面都不成功,执行else
}

Example

package main

import "fmt"

func main() {
    var gender = "男"

    if gender == "男" {
        fmt.Println("男")
    } else if gender == "女" {
        fmt.Println("女")
    } else {
        fmt.Println("啥都不是???")
  }
}

switch case

switch case和if本质是一个东西,但是在某些场景,switch是比if更加简洁的。

代码

package main

import "fmt"

func main() {
    var week = 3
    switch week {
    case 1:
        fmt.Println("周一")
    case 2:
        fmt.Println("周二")
    case 3:
        fmt.Println("周三")
    case 4:
        fmt.Println("周四")
    case 5:
        fmt.Println("周五")
    case 6:
        fmt.Println("周六")
    case 7:
        fmt.Println("周日")
    default://如果上面都没执行,会执行default
        fmt.Println("星期八????")
  }
}

注:在Go中,switch是没有case穿透的。

Go的switch可以case多个值。

package main

import "fmt"

func main() {
    var week = 3
    switch week {
    case 1, 2, 3, 4, 5:
        fmt.Println("上班")
    case 6:
        fmt.Println("周六睡懒觉")
    case 7:
        fmt.Println("周日去旅游")
    default:
        fmt.Println("飞天了???")
  }
}

for

标准for循环

语法

for 初始条件;判断条件;结束条件{
    语句
}

代码

package main

import "fmt"

func main() {
    for i := 0; i < 10; i++ {
        fmt.Println(i)
  }
}

无限循环

谨慎执行！！！

package main

import "fmt"

func main() {
    for{
        fmt.Println("666")
  }
}

for range

for ragne可以很方便循环数组,切片,字符串,map,channel等。

遍历数组示例

package main

import "fmt"

func main() {
    var student_list = [...]string{"张三", "李四", "王五"}
    for index, v := range student_list {
        //index为下标,v是每一个的值
        fmt.Println(index, v)
  }
}

注:

如果数组,切片,字符串
  index是下标,v是值
如果是map
  index是键,v是对(值)
如果是通道
  只有一个值,就是通道内的值

补充:

在Go中,只有for循环,没有while。

for循环就两种方式。

goto

goto可以通过标签在代码间无条件跳转,这就造成了一个局面,如果使用gote过多,会造成逻辑混乱,跳来跳去。

所以,在开发中,要慎用,不到万不得已,不要使用。

示例

package main

import "fmt"

func main() {
  for i := 0; i < 10; i++ {
    for j := 0; j < 10; j++ {
      if j == 2 {
        // 直接跳转到下面的 breakTag 标签
        goto breakTag
      }
      fmt.Printf("%v-%v\n", i, j)
    }
  }
  //要跳转的标签
breakTag:
  fmt.Println("结束for循环")
  }

Operator	##Description
=	Simple assignment operator, converts an expression Assign the value of the formula to an lvalue
=	Assign the value after addition
##-=	After subtracting, assign the value
## Multiply and then assign value
/=	##Divide and then assign the value
%=	##Find the remainder and then assign the value
<<=	Assign value after left shift
##Assignment after bitwise AND
=	Assignment after bitwise OR
##^=	Assignment after bitwise XOR

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