go语言就是golang_1天学会_基础篇_v1.0.3

以你之姓@ 2022-12-21 04:42 98阅读 0赞

<table> 
 <thead> 
  <tr> 
   <th>文件名称</th> 
   <th>版本号</th> 
   <th>作者</th> 
   <th>qq</th> 
   <th>版本</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>go语言就是golang_1天学会_基础篇</td> 
   <td>v1.0.3</td> 
   <td>学生宫布</td> 
   <td>8416837</td> 
   <td>go1.13.4 windows/amd64<br></td> 
  </tr> 
 </tbody> 
</table>

### 相关教程 ###

[go环境-vscode][go_-vscode]  
[基础、web等][web]  
[go web代码生成、基于框架开发][go web]

### 文章目录 ###

*   *   *  相关教程
         *  语法
         *   *  接口 实现接口函数
             *  时间
             *  字符串
             *  list
             *  goroutine 并发
             *   *   *  通道实现'分布式计算'
             *  异常处理
             *  控制台游戏
             *   *  猜数字 二分查找法
         *  解决报错
         *   *  cannot find package "github.com/ethereum/go-ethereum/rpc" in any of:

### 语法 ###

#### 接口 实现接口函数 ####

1.  code

package main
    
    import "fmt"
    
    type Car interface { 
    	run(typeNumber string)
    }
    
    type Jili interface { 
    	sleep()
    	running() // 子类必须实现全部两个接口
    }
    
    type Dihao struct { 
    }
    
    func (dihao Dihao) run (typeNumber string) { 
    	fmt.Println(typeNumber, `-小车running。。。`)
    }
    
    func (dihao Dihao) running() { 
    	fmt.Println(`吉利汽车running。。。`)
    }
    
    func (dihao Dihao) sleep () { 
    	fmt.Println(`-在帝豪车里休息。。。`)
    }
    
    type Honda struct { 
    }
    
    func (honda Honda) run(typeNumber string) { 
    	fmt.Println(typeNumber, `-本田running。。。`)
    }
    
    func main() { 
    	var car Car
    	car = new(Honda)
    	car.run(`凌派`)
    	var jili Jili
    	jili = new(Dihao)
    	jili.sleep()
    	jili.running()
    	car = new (Dihao)
    	car.run(`帝豪`)
    }

1.  output

凌派 -本田running。。。
    -在帝豪车里休息。。。
    吉利汽车running。。。
    帝豪 -小车running。。。

#### 时间 ####

*  基本

package main
    
    import (
    	"fmt"
    	"time"
    )
    
    func main() { 
    	fmt.Println("hg")
    	fmt.Println("Time", time.Now())
    }

*  格式化一下

// 【注意】必须是"2006-01-02 15:04:05",否则格式化不正确
    	fmt.Println("Time", time.Now().Format("2006-01-02 15:04:05"))
    	fmt.Println("Time", now.Year())

#### 字符串 ####

package main
    
    import (
    	"fmt"
    	"strings"
    )
    
    func main() { 
    
    	var strs [3]string
    	strs[0] = "6e0ef25a-32f1-4405-b458-efbde3ff4ec6"
    	strs[1] = "ae632042-1b77-4fd5-b76a-7ac730db8a6c"
    	strs[2] = "204b7324-4ee4-4672-9900-faa8ee392432"
    	replacer := strings.NewReplacer("-", "")
    
    	for i := 0; i < len(strs); i++ { 
    		fmt.Println(replacer.Replace(strs[i]))
    	}
    
    }

Output：  
![在这里插入图片描述][20201114180752968.png_pic_center]

#### list ####

package main
    
    import (
    	"container/list"
    	"fmt"
    )
    
    func main() { 
    
    	table := list.New()
    	table.PushBack(1)
    	table.PushBack("ball")
    	table.PushBack("orange")
    	table.PushBack('x')
    	table.PushFront(88.48)
    
    	fmt.Println("长度", table.Len())
    
    	for i := table.Front(); i != nil; i = i.Next() {  // 末尾i变成nil
    		fmt.Println(i.Value)
    	}
    }

#### goroutine 并发 ####

1.  code

package main
    
    import (
    	"fmt"
    	"time"
    )
    
    
    func doSth(msg string, NUM int) { 
    	for  i := 0; i < NUM; i++ { 
    		time.Sleep(123 * time.Millisecond)
    		fmt.Println(msg)
    	}
    }
    
    func main() { 
    	go doSth("goroutine~", 5)
    	doSth("main thread~", 5)
    }

1.  out:  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NjMDA3Y2MwMDk_size_16_color_FFFFFF_t_70]

###### 通道实现’分布式计算’ ######

package main
    
    import "fmt"
    
    func sum(s []float32, compute_channel chan float32) {  // chan float32 定义通道
    	 var sum float32 = 0
    	for _, v := range s { 
    		sum += v
    	}
    	compute_channel <- sum // 把 sum 发送到通道 compute_channel
    }
    
    func main() { 
    	s := []float32{ 3.5, 9.2, 0.3, 5, 5, 0} // 定义输入
    
    	compute_channel := make(chan float32)
    	go sum(s[:len(s)/2], compute_channel) // 多个goroutine模拟分布式计算 当前场景各计算一半
    	go sum(s[len(s)/2:], compute_channel) // go命令执行后，开始并发
    	x1, x2 := <-compute_channel, <-compute_channel // 从通道 compute_channel 中接收
    
    	fmt.Println(x1, x2, x1+x2)
    }

#### 异常处理 ####

1.  code

package main
    
    import (
    	"errors"
    	"fmt"
    )
    
    func Sqrt(f float64) (float64, error) {  // 多个返回
    	if f < 0 { 
    		return 0, errors.New("math: square root of a negative number is not permitted")
    	}
    	// 模拟实现
    	return 1, nil // 返回多个
    }
    
    func main() { 
    	val,err := Sqrt(-1)
    	if err != nil { 
    		fmt.Println(`结果 == `, val, `
    异常 == `, err)
    	}
    }

1.  output

结果 ==  0 
    异常 ==  math: square root of a negative number is not permitted

#### 控制台游戏 ####

##### 猜数字 二分查找法 #####

*  猜一个1-100以内的自然数

package main
    
    import (
    	"bufio"
    	"fmt"
    	"log"
    	"os"
    	"strconv"
    	"strings"
    )
    
    func main() { 
    	var targetNum float64 = 100
    	var num float64
    	var msg string
    	var count int
    
    	for { 
    		fmt.Println("Please input one number")
    		reader := bufio.NewReader(os.Stdin)
    		input, err := reader.ReadString('\n')
    		input = strings.TrimSpace(input)
    		count++
    
    		num, err = strconv.ParseFloat(input, 64)
    
    		if err != nil { 
    			log.Fatal(err)
    		}
    
    		if num == targetNum { 
    			fmt.Println(count, `真棒，猜对了`)
    			break
    		} else if num > targetNum { 
    			msg = `大了`
    		} else if num < targetNum { 
    			msg = `小了`
    		}
    		fmt.Println(`输入`, num, msg, `第`, count, `次竞猜`)
    	}
    
    }

![在这里插入图片描述][2020111723042676.png_pic_center]

### 解决报错 ###

#### cannot find package “github.com/ethereum/go-ethereum/rpc” in any of: ####

*  解决办法

go get github.com/ethereum/go-ethereum/rpc
    # 如果拉不动，则到gitee或github下载源码

[go_-vscode]: https://blog.csdn.net/cc007cc009/article/details/109821888
[web]: https://blog.csdn.net/cc007cc009/article/details/105871843
[go web]: https://blog.csdn.net/cc007cc009/article/details/110010054
[20201114180752968.png_pic_center]: /images/20221120/92fb210eb4ea40339e5e6dfdd4f58036.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NjMDA3Y2MwMDk_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20210102104346978.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NjMDA3Y2MwMDk=,size_16,color_FFFFFF,t_70
[2020111723042676.png_pic_center]: https://img-blog.csdnimg.cn/2020111723042676.png#pic_center