CrLf

楼主给的特例可以这样：

@echo off&setlocal enabledelayedexpansion
set test=340524
for /f %%a in ('cmd /v /u /c "echo ^!test^!"^|more') do set "str=!str!，%%a"
echo !str:~1!
pause
复制代码

CrLf

仍然是根据楼主的特例写的：

@echo off&setlocal enabledelayedexpansion
set test=340524
for /l %%a in (0 1 9) do set "str=!str:%%a=，%%a!"
echo !str:~1!
pause
复制代码

CrLf

常见的通用方案是：

@echo off&setlocal enabledelayedexpansion
set test=340524
for /l %%a in (0 1 4090) do (
if "!test:~%%a!"=="" goto exitFor
set "test=!test:~,%%a!，!test:~%%a!"
)
:exitFor
echo !test!
pause
复制代码

CrLf

以上一个方案为基础的另一个方案，最长支持100字符长度，速度较快：

@echo off&setlocal enabledelayedexpansion
set test=340524
for /l %%a in (9 -1 0) do (
   set 个位=!个位!9876543210
   set 十位=!十位!%%a%%a%%a%%a%%a%%a%%a%%a%%a%%a
)
set 个位=!test!!个位!
set 十位=!test!!十位!
set /a 长度=1!十位:~99,1!!个位:~99,1!-100
for /l %%a in (1 1 !长度!) do set "test=，!test:~-1!!test:~,-1!"
echo !test:~1!
pause
复制代码

CrLf

和上一个方案思路一致，只是通过调用二分回溯函数来计算长度，对付长字符串时具有优势

@echo off&setlocal enabledelayedexpansion
set test=340524
call :strlen test 长度
for /l %%a in (1 1 !长度!) do set "test=，!test:~-1!!test:~,-1!"
echo !test:~1!
pause

:strlen
setlocal enabledelayedexpansion
set "$=!%1!#"
set len=&for %%a in (4096 2048 1024 512 256 128 64 32 16 8 4 2 1)do if !$:~%%a^,1!. NEQ . 

set/a len+=%%a&set $=!$:~%%a!
endlocal&If %2. neq . (set/a%2=%len%)else echo %len%
exit/b
复制代码

CrLf

或用简便而强大的 js 正则替换：

@set @n=0;/*&echo off&setlocal enabledelayedexpansion
set test=340524
echo !test!|cscript /nologo /e:jscript %0
pause&exit/b*/
WScript.Echo(WScript.StdIn.ReadAll().replace(/(\w)/g,"，$1").replace(/^，/,""))
复制代码

CrLf

第三方当然也是可以的

@echo off&setlocal enabledelayedexpansion
set test=340524
echo !test!|sed "s/./，&/g;s/^，//"
pause
复制代码