batch-file - 使用延迟变量值作为子字符串中的长度值

Question

我正在从日志文件中提取笔记集。通过 FIND/V/N 找到文件中一组标题的行号注释集由仅包含“@@@”的行分隔我使用 findstr 返回此行，它返回为“xxx:@@@”，例如'14:@@@' 或 '149:@@@' 等等。

在下面的代码片段中，进入FOR/IN 循环的变量的典型数据是

• _ndelm = "@@@" ~ 标记注释结束的分隔符
• _infil = "notes.log" 保存数据集的文件
• _atpos = 笔记标题的行位置

在执行期间，enabledelayedexpansion 循环中的局部变量包含以下需要 !..! 的临时值在处理的时刻:

• strel=如上findstr返回的字符串分隔符行
• numel=从strel=='xxx'中提取的行号，一般1-4个字符长
• end = 将成为​​分隔符行的(整数)行号

在此代码片段中，需要 IF 语句来解决我的问题:我找不到在单个 中使用 !end! 的方法SET 语句，因此解决方法是 4 个 IF。:

SET _ndelm=@@@
SET /a _atpos=1
FOR /f "usebackq tokens=1 delims=[]" %%i IN (`FINDSTR /b /l /n /c:%_ndelm% %_infil% `) DO (
SET strel=%%i
CALL stringlen %%i end & rem gets the character length of the delimiter line]
SET /a end-=4
IF [!end!] EQU [1] (SET numel=!strel:~0,1!)
IF [!end!] EQU [2] (SET numel=!strel:~0,2!)
IF [!end!] EQU [3] (SET numel=!strel:~0,3!)
IF [!end!] EQU [4] (SET numel=!strel:~0,4!)
SET /a end=!numel!
IF !end! GEQ %_atpos% GOTO fetchlines
)

理想情况下，我想编写这样的代码

(SET numel=!strel:~0,!end!!)
SET /a end=!numel!

我到处寻找类似的用例，但无济于事，并根据经验尝试了 % 和 ! 的任意组合。

如果有人知道我可以使用的语法，那就太好了:-)

谢谢

文件摘录:

11/01/2020 16:05:29.87 *** DONE *** All Batches [LEFiles needing /r]
 find all batches that should not be run, apply the /r switch and amend 
 accordingly. Start at root and work down the main line before tackling the 
 side branches.
  ~ Main *** done ***
  ~ libs *** done ***
  ~ rest *** done ***
  ~
@@@
11/01/2020 15:18:47.02 >>> open >>> LEfiles runit [add a 'don't run!' switch]
 some batches just can't be -or shouldn't be- run from the help system.
 code a don't run switch [/r]=don't run
@@@
09/01/2020 10:12:52.83 *** DONE *** strcharrepl [bug] abend on "*" to " "
 error message '= % was unexpected at this time.' after returning from a call to
 nameFiledatetime which itself crashes on spaces - workaround for that needed
 Suspect it's the same problem - returning a string with spaces is the generic
 issue that needs a solution.
 Maybe always return with quotes and then strip those? 
 ~soln [strcharrepl] not much that can be done because redirection chars
  always act in re-dir ways. Added notes to provide guidance in use.
 ~soln [zFN] surround filename with quotes and replace spaces with backslashes
  before call, replace with spaces after.
@@@

Answer 1

For %%e in (!end!) Do set numel=!strel:~0,%%e!

诀窍是使用 for 循环参数，因为在执行延迟扩展之前扩展参数。