[BATCH]批处理中enabledelayedexpansion启动变量延迟

Jan 18, 2020#batch #powershell57

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This article discusses the use of "setlocal enabledelayedexpansion" in batch processing to avoid real-time variable expansion in loops. It provides a simple example of defining and calculating variables, and then calculating the results. The article explains how to use "set /A" to temporarily store the intermediate calculation results, and how to combine expressions into one line using "&". The article also includes code examples and explains the difference between using and not using "enabledelayedexpansion".

一个简单的需求，批量定义变量并运算赋值，再对获取变量计算的结果值

方法： 1. 使用 SET /A 方式暂存表达式的中间计算结果 2. 使用 setlocal enabledelayedexpansion 避免解释器在循环体中实时展开变量 3. 使用 & 合并表达式为 1 行启用 setlocal enabledelayedexpansion。启动变量延迟

@echo on
set var4="test"
for /l %%i in (1,1,3) do set var%%i=%%i
echo %var1%
echo %var2%
echo %var3%
echo %var4%
setlocal enabledelayedexpansion
for /l %%j in (1,1,3) do ( set /a t= var%%j & echo !t! )
for /l %%j in (1,1,3) do (
set /a t= var%%j
echo !t!
)
endlocal

pause 输出 1 2 3 4

关闭 enabledelayedexpansion 输出 4 4 4 4

关于 setlocal 和 enabledelayedexpansion https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/cc772046(v=ws.11)?redirectedfrom=MSDN