help with IF statement

[blastman]

Hi guys,

I'm having problems with my if statement....

I want to compare %oldprice% (which is the last modified date of a file in a  certain directory) with %newdateP% (which is the date of the last used file, exported to a txt file in the format "11/02/2008 12:16")

Code: [Select]

REM Searching for latest Graphic file and setting varaible's

set directory="t:\graphic_updates"
cd /d %directory%

FOR /F  %%i IN ('dir /b /a-d /od') DO (
   set lastfileP=%%i
   set newdateP=%%~ti
   )

set /p oldprice=<"T:\log file\price.txt"

if /i "%newdateP%" GTR "%oldprice%" (goto update)

echo.No update to be done
pause

:update
echo.Update to be done.
del "T:\log file\price.txt"
echo.%newdateP%>>"T:\log file\price.txt"
pause

The problem is that no matter what date is in the txt file, it still whats to update.

If change the date in the price.txt to;

"10/02/2008 12:16" - it wants to update
"11/02/2008 12:16" - it wants to update - this is the exacly the same as %newdateP% and I don't want it to update.
"12/02/2008 12:16" - it doesn't want to update


I've tried it will LSS and swapping the varibkles around but i still get the same response.

any ideas???

cheers guys 

[Sidewinder]

It is easier (and more logical) to compare dates in YYYYMMDD format. I would suggest you parse out the day, month and year values and swap them around.

On a more practical note, your code as written will end up in the :update code; either from the goto or by falling into after the pause statement. Try using a goto :eof in place of the pause.

 

[Dias de verano]

The GTR, LSS EQU etc tests are arithmetic tests, and give unexpected results when used to compare strings, for example "2" GTR "101" will return true because ASCII string comparisons stop if the first character of either string is greater than the other, and 2 has a higher ASCII code than 1.

Better to parse out the numbers and use set /a to load a numerical variable with e.g. 20080222 which is today's date in yyyymmdd format. Don't bother with hhmmss because batch arithmetic will run out of bits of precision.

[blastman]

The GTR, LSS EQU etc tests are arithmetic tests, and give unexpected results when used to compare strings, for example "2" GTR "101" will return true because ASCII string comparisons stop if the first character of either string is greater than the other, and 2 has a higher ASCII code than 1.

Better to parse out the numbers and use set /a to load a numerical variable with e.g. 20080222 which is today's date in yyyymmdd format. Don't bother with hhmmss because batch arithmetic will run out of bits of precision.

I understand what you mean about those co-op's being numerical so having strange results with stings.

How would I convert the %newdateP% (which is in 11/02/2008 12:16 format) to 11022008 then???

cheers for the help.

[gpl]

Assuming your regional settings are UK format (from your example I think that is safe), use this :

Set Today=%Date:~6,4%%Date:~3,2%%Date:~0,2%

Change Date to newdateP in each of the 3 occurrences above for your code.
Graham

[blastman]

sorry. I'm not sure i get it.

that line you've posted will make a variable 'today' with todays date in the right format. yes??

[gpl]

Sorry, I wasnt as clear as I could have been - I just pasted an example from a bit of code Im working on.

Change your line

Code: [Select]

if /i "%newdateP%" GTR "%oldprice%" (goto update)
to

Code: [Select]

if /i "%newdateP:~6,4%%newdateP:~3,2%%newdateP:~0,2%" GTR "%oldprice:~6,4%%oldprice:~3,2%%oldprice:~0,2%" (goto update)
note - its is just 1 line above, ignore the wrapping on the screen

Graham

[Dias de verano]

gpl has noted correctly that for a numerical date comparison to work, the date number has to be in the format YYYYmmDD with the year first

thus

yesterday : 20080225
today     : 20080226
tomorrow  : 20080227

[blastman]

OK. I've cheated.....


I have some UNIX tools installed on this machine so I've used 'sed' and 'cut' to take the date from the format the it is currently in and rearrange to the YYYYmmdd format.

Although my if statement still seems to to 'update' even if both variables that it's compairing are the same.  (and no I'm not using GEQ or LEQ co-op's)

I'll post some code. (it bit look abit complex............)

[blastman]

hey,

I managed to get it working!! 

Turns out it was a simple mistake.

nevermind, it's all working now.

cheers for your input guys.