[已解决]求助批处理if语句内拼接字符串为什么不行？

hardstone

1. set M=@
   
2. if "1" == "1" (
   
3.     echo !!!!!!!!!!
   
4.     echo 0%M%
   
5.     set "x=0%M%"
   
6.    
   
7.     echo %x%?
   
8.     :: why it echo just one
   
9.     echo !!!!!!!!!!
   
10. )

复制代码

echo出的结果是?而不是0@?

77七

1. @echo off
   
2. set M=@
   
3. if "1" == "1" (
   
4.         echo !!!!!!!!!!
   
5.         setlocal enabledelayedexpansion
   
6.         echo 0!M!
   
7.         set "x=0!M!"
   
8.        
   
9.         echo !x!?
   
10.         endlocal
    
11.         rem why it echo just one
    
12.         echo !!!!!!!!!!
    
13. )
    
14. pause

复制代码

参考：   [教程汇总]批处理中的变量延迟扩展、变量嵌套

ShowCode

回复 1# hardstone

1. @echo off
   
2. setlocal enabledelayedexpansion
   
3. set "M=@"
   
4. if "1" == "1" (
   
5.     echo ----------
   
6.     echo 0%M%
   
7.     set "x=0%M%"
   
8.     echo !x!
   
9.     echo ----------
   
10. )
    
11. pause

复制代码

aloha20200628

回复 1# hardstone

除了采用变量延迟应对 ‘预处理’，还可采用call+%%v%%方法应对 ‘预处理’ ...

1. 
   
2. @echo off
   
3. set M=@
   
4. if "1" == "1" (
   
5.     echo !!!!!!!!!!
   
6.     echo 0%M%
   
7.     call set "x=0%%M%%"
   
8.     call echo %%x%%?
   
9.     echo !!!!!!!!!!
   
10. )
    

复制代码

hardstone

谢谢大佬们解答！