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parsing strings
Posted: 04 Nov 2022 14:50
by TekFreak260
I am trying to write a batch file that basically parses a string and determines a few things based on the filename. So for example, a test filename would be A01B_NCS_Tab_1102.pdf. My task is to read in all file names from the current directory and determine if the number (2nd and 3rd characters which form a page number) are odd or even. Then find out if the 4th character, is a B or a C to be able to filter things further. Lastly Be able to look to see if the filename has the word "Tab" in it. Then depending on what those variables, would determine where the file gets moved to. I tried using a "dir /b *.pdf" and dumping to a file to get just the filenames from the current directory then reading in the file using
FOR /F "Tokens=1" %%G in (filename.txt) do (
set str=%%G
set PgNum=%str:~1,2%
echo %PgNum% >>filename2.txt
)
but the file is empty and i get "echo is off" on my dos window. Which tells me for some reason the variables are all empty. What am i doing wrong?
Re: parsing strings
Posted: 04 Nov 2022 23:30
by T3RRY
When working with variables in loops or code blocks, Variables are parsed with the value the had prior to the commencement of the codeblock
To access their current value, Delayed expansion is required to be enabled and variables expanded using the ! reference character, IE: !variable!
Code: Select all
@Echo off & CD /D "%~dp0"
REM clear any pre-existing definitions of IsPROPERTY; supress error if no definitions.
2> nul (For /f "tokens=1 Delims==" %%G in ('Set Is')Do Set "%%G=")
for /F "tokens=1* Delims=_" %%G in ('Dir /B *_*_*_*.pdf')Do (
Set "Lead=%%G"
Set "filename=%%G_%%H"
REM enable environment for delayed expansion. Enabled during each loop in order to preserve ! characters in filenames if present
Setlocal EnableDelayedExpansion
REM enable below line to see filename being processed
REM Set filename
REM check filename for _Tab_ string; define IsTab if True
If not "!filename:_Tab_=!" == "!filename!" Set "IsTab=True"
REM Isolate Last character of first _ delimited token and assign true state as IsCHAR
Set "Is!Lead:~3,1!=true"
REM remove first and last characters of first _ delimited token to isolate page number
Set "Lead=!Lead:~1,-1!"
REM Test if leading character is 0; remove if true
If "!Lead:~0,1!" == "0" Set "Lead=!Lead:~1,1!"
REM Use modulous operation on the page number in an expression designed to trigger a divide by zero error if true
2> nul Set /A "1/(Lead %% 2)" && (
REM conditional operation if no divide by zero error
Set "IsOdd=true"
) || (
REM conditional operation upon divide by zero error
Set "IsEven=true"
)
Rem Displays states. Use combinations of If defined IsPROPERTY to enact required logic.
Set Is
Rem perform any logic required for each file prior to Endlocal
Endlocal
)
Pause
Goto:Eof