Quickest way to remove trailing zeros from a string?

[CirothUngol]

Just stopped to post the code being used...

Code: Select all

:math_trailing numVar -- removes trailing zeros
SET m_t=4096
FOR /L %%X in (1,1,13) DO IF DEFINED %~1 FOR %%Y IN (!m_t!) DO (
   IF "!%~1:~-%%Y!"=="!zeros:~-%%Y!" SET "%~1=!%~1:~0,-%%Y!"
   SET /A m_t/=2
)
IF DEFINED %~1 IF "!%~1:~-1!" EQU "." SET "%~1=!%~1:~0,-1!"
EXIT /B 0

Small, simple, full-featured and works like a charm. Thanks again guys, you'll be the first to know next time I hit a wall. ^_^

[Aacini]

I think that this method should run faster (and it is much simpler):

Code: Select all

@echo off
setlocal EnableDelayedExpansion

set "numStr=000000000000000001002300045600000000000"

for /F "tokens=* delims=0" %%a in ("%numStr%") do set "answer=%%a"
set "l="
set "r="
set "answer=%answer:0=" & (if defined r set "answer=!answer!!l!!r!" & set "l=") & set "l=!l!0" & set "r=%"
if defined r set "answer=!answer!!l!!r!"

echo Answer: %answer%

Antonio

[aGerman]

Never thought about using this technique for that task.
Great idea, Antonio!

Steffen

[CirothUngol]

I think that this method should run faster (and it is much simpler)

Faster, I have no doubt. Clever and elegant, sure. Simpler... don't know about all that. I certainly see how it works, but definately falls into the "I'd have never thought of that" category. Love it!

My issue with it is max string size. The replacement adds dozens of characters, so it gives out way too quick. Awesome technique, though! I'm adding that page to the dozen+ Dostips tabs that I have open right now. Looks like another fun Saturday spent learning about WinNT batch. ^_^

[penpen]

I think this is the fastest code that also works on full environment variables:

Code: Select all

@echo off
setlocal enableExtensions enableDelayedExpansion

set "numStr=000000000000000001024000000000000000000000000000000000000000000000"

for /F "tokens=* delims=0" %%a in ("!numStr!") do set "answer=%%a"
set /a "r=range=0"
if "!numStr:~-1!" == "0" (
   for %%a in (4096 2048 1024 512 256 128 64 32 16 8 4 2 1) do (
      set /a "r+=%%~a"
      for %%b in ("!r!") do for /f "delims=0" %%c in ("!answer:~-%%~b!") do set /a "r-=%%~a"
   )
   set "range=0,-!r!"
)
set "answer=!answer:~%range%!"

set answer

goto :eof

penpen