中国DOS联盟

I'm sorry, maybe I'm too stupid. I've read all about this in the forum but still don't understand.

@echo off

echo Remove quotes:
call :replace 1.txt "

echo.
echo Replace characters:
call :replace 1.txt "Thank you" "Thank you"

pause>nul
goto :eof

:replace
setlocal ENABLEDELAYEDEXPANSION
for /f "tokens=1* delims=" %%i in (%1) do set var=%%i & echo !var:%2=%3!
endlocal
goto :eo
For this batch script, I just can't figure out what it means. Especially the part!var:%2=%3! in for /f "tokens=1* delims=" %%i in (%1) do set var=%%i & echo!var:%2=%3!. I don't understand the part about! either. Can someone give me some pointers? It's best to explain it with the above example. I looked at the help for the set command and didn't understand what the unary operator means... Thanks ah.

　　Search in the forum. Keyword: "variable delay".

I've searched, but I still don't understand. Sorry, I'm a bit slow.

　　Re xue2ye:

　　Let me briefly explain it to you:

　　Because the command interpreter (%comspec%) expands the variables in the for command to their values first when executing the for command. So, when we execute, some variables are obtained according to the for command. In this case, the variable is not defined yet when the command interpreter interprets (expands) it, and obviously we can't get what we want. If we want the variable value to be expanded after the for command is executed, we need to enable the variable delay function to achieve this purpose. To enable the variable delay function, we must define it first before the for command. We can use "setlocal ENABLEDELAYEDEXPANSION" to enable the variable delay function. When referring to the variable again, we need to enclose the variable with two "!" (for example, "!var!") to expand the variable to its value.

　　Due to time constraints, the explanation is not very detailed. You can search the forum for more detailed descriptions about variable delay.

The `for /f "tokens=1* delims=" %%i in (%1) do set var=%%i & echo !var:%2=%3!` is a Windows batch command.

Here's a breakdown:

- `for /f`: This is a file - reading loop command. It reads lines from a file specified by `%1`.
- `"tokens=1* delims="`: It means it will split each line into tokens. Here, `delims=` means the delimiter is not set, so each line is treated as a single token, and `%%i` will hold the whole line.
- `do set var=%%i`: It sets the variable `var` to the current line read.
- `&`: It is a command separator.
- `echo !var:%2=%3!`: It echoes the value of `var` with the substring replacement. Here, it replaces all occurrences of the string stored in `%2` with the string stored in `%3` in the variable `var`.

The part `!var:"感谢您"="谢谢您"!` is using this substring replacement functionality. It takes the value of `var` and replaces all instances of "感谢您" with "谢谢您".

　　 !var:“感谢您”=“谢谢您”!——Replace all "感谢您" in variable var with "谢谢您"!

I'm sorry, but I still don't understand. Why use "Thank you" and "Thanks a lot"? If I use others, it doesn't seem to work. I've looked at most of the posts about set in the forum, and they mostly only talk about the principle, not the specific usage. Can you explain it?

Some things are indeed very abstract. Most people won't understand if you don't give an example. Please, all moderators and experts, when answering questions, try to add some examples to facilitate understanding. Thanks

I just can't understand. If I follow to do, I can do it myself, but I can't when I want to do it by myself. You give me a simple example, please... Thank you.

@echo off

    set str=www.cn-dos.net

    echo 替换前变量str的内容为: %str%

    echo 执行set str=%%str:www=bbs%%

    echo 替换后变量str的内容为: %str:www=bbs%

pause

From the code format, it seems like I wrote it, but now it seems the code is really immature.
As for "why use 'Thank you' and 'Thank you'", that has to be combined with the content of 1.txt to see, because the parameter %1 is 1.txt.
It is suggested that beginners do not study parameters and variables together, first understand each set one by one and then combine with others.

@echo off

    set str=www.cn-dos.net

    echo The content of variable str before replacement is: %str%

    echo Execute set str=%%str:www=bbs%%

    echo The content of variable str after replacement is: %str:www=bbs%

pause

What does the sentence `set str=%%str:www=bbs%%` mean?

Originally posted by xue2ye at 2006-11-14 20:33:
What does the line "set str=%%str:www=bbs%%" mean?

This line is to show you that to display a %, you need "%%".
After executing "echo set str=%%str:www=bbs%%", it will display: set str=%str:www=bbs%

Assign "www.cn-dos.net" to the variable "str", then use %str:www=bbs% to replace "www" with "bbs" in "www.cn-dos.net"

Oh, I still don't understand it... 555555555

Learning doesn't require novelty; it should start from basic things. It is suggested that dshh98 first carefully read the basic DOS commands, practice more, and then explore advanced things.