windows 如何从批处理文件中的函数返回值？
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How do I return a value from a function in a batch file?
提问by AnthonyM
I have the following batch file
我有以下批处理文件
@echo off
setlocal EnableDelayedExpansion
for /f "delims==" %%J in (File_List.txt) do (
call :setDate %%J MYD
echo/Date is: %MYD%
)
endlocal &goto :eof
:setDate
SETLOCAL ENABLEEXTENSIONS
echo %1
echo %~2
set NAME=%1
set NAME=%NAME:~-11%
echo %NAME%
echo %~2
endlocal&set %2=%NAME%&goto :eof
but with File_List.txt containing file2012-05.csv
但 File_List.txt 包含 file2012-05.csv
I get
我得到
file2012-05.csv
MYD
2012-05.csv
MYD
Date is:
How do I actually get the function setDate to return the value I want?
我如何真正让函数 setDate 返回我想要的值？
回答by Elwood
As I don't understand from your script what you want to achieve, I reply (for completeness) to the original subject: returning a value from a function.
由于我从你的脚本中不明白你想要实现什么，我回复（为了完整性）原始主题：从函数返回一个值。
Here is how I do it:
这是我如何做到的：
@echo off
set myvar=
echo %myvar%
call :myfunction myvar
echo %myvar%
goto :eof
:myfunction
set %1=filled
goto :eof
Result is:
结果是：
empty
filled
回答by Eitan T
The batch interpreter evaluates %MYD%at parse time, and at that time it's empty. That's why you have Delayed Expansion. Change this line:
批处理解释器%MYD%在解析时进行评估，当时它是空的。这就是为什么你有延迟扩展。改变这一行：
echo/Date is: %MYD%
to this:
对此：
echo/Date is: !MYD!
and it will work like you want, because then it tells the interpreter to evaluate MYDat run-time.
它会像你想要的那样工作，因为它会告诉解释器MYD在运行时进行评估。
