编程语言-go：变量声明，数据类型，流程控制，循环语句

女爷i 2022-03-25 09:52 253阅读 0赞

go语言sdk下载：[https://golang.google.cn/dl/][https_golang.google.cn_dl]

# 1，go变量/常量 #

保留的关键字： var , const

<table> 
 <thead> 
  <tr> 
   <th align="left">变量</th> 
   <th align="left">常量</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">var a int =9 <br> var a =9 <br> a:=9 //自动推断类型</td> 
   <td align="left">const a int = 9</td> 
  </tr> 
 </tbody> 
</table>

# 2，go数据类型 #

## a, 基本数据类型 ##

<table> 
 <thead> 
  <tr> 
   <th></th> 
   <th align="left">整数</th> 
   <th>浮点数</th> 
   <th>布尔类型</th> 
   <th>字符串</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>有符号</td> 
   <td align="left">int, &nbsp; int8, &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;int16, &nbsp;int32</td> 
   <td>float32,float64</td> 
   <td></td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>无符号</td> 
   <td align="left">unit, unit8[byte], unit16, unit32</td> 
   <td></td> 
   <td></td> 
   <td></td> 
  </tr> 
  <tr> 
   <td>固定值</td> 
   <td align="left"></td> 
   <td></td> 
   <td>true,false</td> 
   <td>“xx”</td> 
  </tr> 
 </tbody> 
</table>

补充：int和unit 表示范围：等于cpu位数(32、64) \* byte

## b, 引用数据类型 ##

<table> 
 <thead> 
  <tr> 
   <th align="left">数组</th> 
   <th align="left">切片</th> 
   <th align="left">map</th> 
   <th align="left">通道</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">var arr [3]int</td> 
   <td align="left">var slices []int <br> slices := make([]int,3)</td> 
   <td align="left">var map1 map[string]string</td> 
   <td align="left">c:=make(chan int)<br> c:=make(chan int，2)</td> 
  </tr> 
  <tr> 
   <td align="left">var arr= [3] int{1,2,3} <br>var arr= […] int{1,2,3}</td> 
   <td align="left">var slices= [] int{1,2,3}<br> slices := arr[:]</td> 
   <td align="left">map1:=make(map[string]string) <br>map1:=make(map[string]string,3)</td> 
   <td align="left">发送数据： &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;c &lt;- 1 <br> 接收数据： res := &nbsp;&lt;- c</td> 
  </tr> 
 </tbody> 
</table>

补充：  
数组是定长的，而切片是长度可变的，由数组获取切片： var slices=arr\[0:2\]  
切片的函数：slices = append(slices, 1,2,3), slices2 = copy(slices)  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70]

# 3,流程控制： if-else, switch-case #

vim if-else.go  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70 1]

root@wabg-GA-MA770T-UD3P:/home/wabg/txt# go run if-else.go 
    1==1
    1==1

vim switch-case.go  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70 2]

root@wabg-GA-MA770T-UD3P:/home/wabg/txt# go run switch-case.go 
    young man
    young man

# 4，go循环语句 #

只有for循环，没有while循环  
vim for.go  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70 3]

root@wabg-GA-MA770T-UD3P:/home/wabg/txt# go run for.go 
    1
    2
    3
    1
    2
    3
    1 1
    2 2
    3 3
    ....
    ....
    ....

[https_golang.google.cn_dl]: https://golang.google.cn/dl/
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