for循环中未设置的批处理脚本变量无效 [英] batch script variable unset in for loop has no effect

问题描述

下面是我的脚本.我正在尝试查看下面一级的文件夹，并仅选择那些文件夹，因此〜-9从路径中提取了最后9个字符.但是set var =不会取消设置变量，因为输出将返回相同的文件夹名称，重复#次.另外，批处理不允许我直接在%% i上执行此提取技巧，因此需要局部变量.

Below is my script. I am trying to look into folders one level below and pick out only those folders, hence the ~-9 which extracts the last 9 chars from the path. But the set var= does not unset the variable because the output comes back with the same folder name repeated # times. Also batch doesn't allow me to do this extract trick directly on %%i, hence the need for the local variable.

如何清除此变量，以便在下一次迭代中采用新值?

How do I clear this variable so that it takes the new value in the next iteration?

@echo off
 for /d %%i in (%1\*) do (
  set var=%%i
  echo %var:~-9%
   set "var="
)

推荐答案

http://judago.webs. com/variablecatches.htm 解释了我的问题.魔术线是setlocal enabledelayedexpansion，并将var称为echo！var:〜-9!. ！ vs％...哇！ cmd仍然令我惊讶.

http://judago.webs.com/variablecatches.htm has an explanation for my problem. The magic lines were setlocal enabledelayedexpansion and calling var as echo !var:~-9!. ! vs % ...wow! cmd still amazes me.

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