extract number from string from another file-CodePudding

I am currently working on a batch file that is supposed to read a version number from another file.

Basically, I just need to extract the string from the other document and get the number from it (number changes over time).

set dir=..\folder1\file1.vcxproj

:: I want to get a string from %dir% with a specific beginning and then extract the version number from it
set string=... ("<PlatformToolset>*")
set vernum=... ("..>v142<..)

Thats what I want to achieve:

echo %string%
   <PlatformToolset>v142</PlatformToolset>
echo %vernum%
   142

I hope I could describe my problem. Unfortunately I have little experience with cmd and it is difficult for me to articulate myself in this respect.

I hope someone can still help :)

CodePudding user response：

dir is a poor name for a variable for two reasons. First dir is a keyword in batch, and then it implies that it's a directory when it seems to be a file.

Use set "var1=value" for setting STRING values - this avoids problems caused by trailing spaces. Quotes are not needed for setting arithmetic values (set /a)

So presuming that what you're doing is to extract the 142 from the string
<PlatformToolset>v142</PlatformToolset> found in the file dir (please change that name)

for /f "tokens=1,2delims=<> " %%b in ('type "%dir%"') do if "%%b"=="PlatformToolset" set "vernum=%%c"
set "vernum=%vernum:~1%"

note that the location and quote type (' or ") are critical.

The for reads each line of the file and analyses that line, assigning the first "token" (1) to %%b and the second (2) to %%c.

The line is regarded as being
<delimiter sequence><token1><delimiter sequence><token2><delimiter sequence><token3><delimiter sequence><token4>

A delimiter sequence is one or more of any of the characters specified in the delims= option; in this case, <, > and Space

So - where %%a (token 1) is PlatformToolset, we want to assign %%c (token 2) to vernum

so vernum will become v142 with a file containing the test line you've posted.

And the hieroglyphics behind the set command is explained by set /? from the prompt - it takes the value in vernum, starting at "character 1" (where the character numbering starts at 0) and assigns the result to the variable vernum

for more detail about for gymnastics, see for /? from the prompt.