special chars in 'set' string substitution
Liviu
with an '*' asterisk or contains an '=' sign.
I've tried several variations using combinations of escaping/quoting
and 'enabledelayedexpansion', to no avail. Better luck, anyone?
Liviu
Timo Salmi
> The '%variable:replace=with%' syntax fails when 'replace' starts
> with an '*' asterisk or contains an '=' sign.
179} How to replace an asterisk "*" in an environment variable?
http://www.netikka.net/tsneti/info/tscmd179.htm
All the best, Timo
--
Prof. Timo Salmi, Vaasa, Finland
http://www.netikka.net/tsneti/homepage.php
Useful CMD script tricks http://www.netikka.net/tsneti/info/tscmd.php
Liviu
> On 06.08.2011 07:53 Liviu wrote:
>> The '%variable:replace=with%' syntax fails when 'replace' starts
>> with an '*' asterisk or contains an '=' sign.
>
> 179} How to replace an asterisk "*" in an environment variable?
> http://www.netikka.net/tsneti/info/tscmd179.htm
Thanks for the pointer and the linked old thread.
Neither answers however what I was actually looking for, which was
a syntax quirk to maybe take advantage of the builtin functionality,
without external programs/scripts, and avoiding char-by-char loops.
FWIW a replace-any-char-with-whatever routine is copied below.
Liviu
@rem ===================================
:: %1 = env-var holding !%1! input string
:: %2 = character to be replaced n.b. "=" equal sign must be quoted
:: %3 = replacement string, or "" to remove !%2!
:: %4 = env-var to receive the %1:%2=%3 end result
:set.subst.char
if "!errorlevel!"=="%errorlevel%" (
setlocal disabledelayedexpansion
call :set.subst.char.main %*
endlocal & set "%~2=!%~2!"
goto :eof
)
:set.subst.char.main
setlocal enabledelayedexpansion
set "string="
set /a index=0
:set.subst.char.loop
set "char=!%~1:~%index%,1!"
if "!char!"=="" goto :set.subst.char.done
if "!char!"=="%~2" (
set "string=!string!%~3"
) else (
set "string=!string!!char!"
)
set /a index+=1
goto :set.subst.char.loop
:set.subst.char.done
endlocal & set "%~4=%string%"
goto :eof
@rem ===================================
jeb
>
> Neither answers however what I was actually looking for, which was
> a syntax quirk to maybe take advantage of the builtin functionality,
> without external programs/scripts, and avoiding char-by-char loops.
>
> FWIW a replace-any-char-with-whatever routine is copied below.
>
> Liviu
A solution which search for the stars with a FOR /F loop,
so it's should be faster than a complete loop over all characters
@echo off
setlocal EnableDelayedExpansion
rem replace all "*" with "."
set "replace=."
set "var=*One**two***three"
rem Add dummy char to accept also a star in front
set "var=#!var!"
:replaceLoop
for /F "tokens=1 delims=*" %%A in ("!var!") do (
set "prefix=%%A"
set "rest=!var:*%%A=!"
if defined rest (
set "rest=!REPLACE!!rest:~1!"
set Again=1
) else set "Again="
set "var=%%A!rest!"
)
if defined again goto :replaceLoop
set "var=!var:~1!"
echo !var!
exit /b
jeb
Liviu
>
> A solution which search for the stars with a FOR /F loop,
> so it's should be faster than a complete loop over all characters
Thanks, and something along those lines can be worked out to
replace _single_ "*" asterisks within a given string. However, the
technique cannot be expanded to cases where the search string starts
with a "*" and is more than one character long (which was in fact
the question posed originally) - for example, it can't delete "*.*" from
a string, or replace "*.111" with "*.222".
To do a full-fledged find-and-replace with arbitrary strings, one
still needs to write a manual loop (which I called "char-by-char" but
would probably be better described as "match-by-match").
> @echo off
> setlocal EnableDelayedExpansion
> rem replace all "*" with "."
> set "replace=."
> set "var=*One**two***three"
>
> rem Add dummy char to accept also a star in front
> set "var=#!var!"
> :replaceLoop
> for /F "tokens=1 delims=*" %%A in ("!var!") do (
> set "prefix=%%A"
> set "rest=!var:*%%A=!"
> if defined rest (
> set "rest=!REPLACE!!rest:~1!"
> set Again=1
> ) else set "Again="
> set "var=%%A!rest!"
> )
> if defined again goto :replaceLoop
> set "var=!var:~1!"
> echo !var!
> exit /b
FWIW the code above has some problems if !replace! itself contains
"*" asterisks, or if either string has exclamation "!" marks. Nothing
which can't be fixed, I think, just noting it for readers who may come
across this post later - including myself ;-)
Liviu