@echo off
set "str=c d e f"
echo %str: =，%
pause
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@echo off&setlocal enabledelayedexpansion
set "str="
for %%a in (c d e f g) do set str=!str!，%%a
::这里用 for 指代实际情况中的 for /f 获取输入，意思意思的意思
set "str=%str:~1%"
echo !str!
pause
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setlocal enabledelayedexpansion
for /f "delims=" %%a in ('wmic logicaldisk get name^|find ":"') do (
   set d=%%a
   set "str=!str!，!d:~,1!"
)
echo %str:~1%
pause
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