Arithmetic inside Round brackets leads to Missing operand

[BoQsc]

I tried to use arithmetic inside IF statement

Code: Select all

		SET "Result=8"
		SET /A "Result=%Result% * 2"
		echo %Result% asdfghjkl

and I've got error saying Missing operand I wonder if I need to EnableDelayedExpansion for arithmetic to work inside the IF statement

Full script

Code: Select all

@ECHO OFF
REM Get current Year and Month for Windows 10
set "year_now=%date:~2,2%";
set "month_now=%date:~5,2%";

echo %year_now% 
echo %month_now%

set "releaseCycle=Interim";
IF "%releaseCycle%"=="LTS" (
	echo useful
) ELSE IF "%releaseCycle%"=="Interim" (
	IF %month_now% LSS 04 (

		SET "Result=8"
		SET /A "Result=%Result% * 2"
		echo %Result% asdfghjkl
	)
  echo interim here
) ELSE IF "%releaseCycle%"=="Daily" (
	echo useful
) ELSE (
	echo useful
)


pause

Output:

Code: Select all

20
03
Missing operand.
 asdfghjkl
interim here

[dbenham]

SET /A is the one case where you don't need delayed expansion because SET /A can expand variables directly - there is no need to use % or ! expansion.

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set /a "result=result*2"
:: or better yet
set /a "result*=2"

But why do you initially set result to 8 in the first place?
why not

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set /a "result=8*2"
:: or simply
set "result=16"

But your ECHO statement must use delayed expansion because it is within the IF block that sets the variable
You will need SETLOCAL EnableDelayedExpansion somewhere earlier in your script, and then

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echo !result! asdfghjkl

But honestly with your simple example I would have

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set "result=16"
echo 16

Though I suppose your script is not really functional, and designed just to demo an issue.


Dave Benham

[BoQsc]

SET /A is the one case where you don't need delayed expansion because SET /A can expand variables directly - there is no need to use % or ! expansion.

Code: Select all

set /a "result=result*2"
:: or better yet
set /a "result*=2"

But why do you initially set result to 8 in the first place?
why not

Code: Select all

set /a "result=8*2"
:: or simply
set "result=16"

But your ECHO statement must use delayed expansion because it is within the IF block that sets the variable
You will need SETLOCAL EnableDelayedExpansion somewhere earlier in your script, and then

Code: Select all

echo !result! asdfghjkl

But honestly with your simple example I would have

Code: Select all

set "result=16"
echo 16

Though I suppose your script is not really functional, and designed just to demo an issue.


Dave Benham

You are correct, that' s just a simplification and demonstration.

I guess I won't avoid using EnableDelayedExpansion in this kind of script.

Thank you.

[BoQsc]

Code: Select all

@ECHO OFF
SETLOCAL EnableDelayedExpansion

REM Get current Year and Month for Windows 10
SET "year_now=%date:~2,2%";
SET "month_now=%date:~5,2%";

SET "releaseCycle=Interim";
IF "%releaseCycle%"=="LTS" (
	echo "Haven't been implemented";
) ELSE IF "%releaseCycle%"=="Interim" (
	IF %month_now% LSS 04 (
		echo ----Here----
		SET /A "year=!year_now! - 1";
		echo ----Here----
		SET "release_version=!year!.10"
		echo !release_version!;
	)
	IF %month_now% LSS 10 (
		IF %month_now% GEQ 04 (
			SET "release_version=!year_now!.04"
			echo !release_version!;
		)
	)
	IF %month_now% GEQ  10 (
		SET "release_version=!year_now!.10"
		echo !release_version!;
	)
) ELSE IF "%releaseCycle%"=="Daily" (
	echo "Haven't been implemented";
) ELSE (
	echo "Haven't been implemented";
)
pause

Output:

Code: Select all

----Here----
Missing operator.
----Here----
19.10;

[dbenham]

FYI - No need to create a separate topic when this last question is obviously related to the previous.

The ; at the end of the statement is causing the problem. SET /A sort of is expecting a second computation, although the proper symbol to use for multiple computations is a comma. Remove the semicolon and it works without error.

Why are you still explicitly expanding the variable? It works, but as I showed in my last post, that is not needed when using SET /A. You could use SET /A "YEAR=YEAR_NOW - 1"

Your way of dealing with dates is not good as it depends on the locale settings for the computer. For example, %date% on my machine yields Fri 03/13/2020 which completely breaks your code.

You should be using FOR /F with WMIC OS GET LOCALDATETIME to get the date and/or time in a way that can be parsed reliably. There is another WMIC option to get the various date/time components separately, but I cannot remember off the top of my head.

Your SET /A arithmetic will fail when you get a number like 08 or 09 because 0 prefixed values are treated as octal notation. A simple solution is to prefix the value with 1 and then subtract 100.
For example:

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set month=09
set /a "PrevMonth=1%month%-100"

Note that in this case you must explicitly expand the month value to get the correct result. SET /A "PREVMONTH=1MONTH-100" will NOT work.


Dave Benham

[BoQsc]

Why are you still explicitly expanding the variable? It works, but as I showed in my last post, that is not needed when using SET /A. You could use SET /A "YEAR=YEAR_NOW - 1"

Note that in this case you must explicitly expand the month value to get the correct result. SET /A "PREVMONTH=1MONTH-100" will NOT work.

I do believe you answered that yourself.
I just though that it will relieve the mental-load while reading and understanding that part of script.

FYI - No need to create a separate topic when this last question is obviously related to the previous.

Understood, won't happen again.

The ; at the end of the statement is causing the problem. SET /A sort of is expecting a second computation, although the proper symbol to use for multiple computations is a comma. Remove the semicolon and it works without error.

That's a mild mistake of mine, I'm glad I didn't put ; at the end of every statement.
Although would have helped to figure out the cause of this on my own.

Your way of dealing with dates is not good as it depends on the locale settings for the computer. For example, %date% on my machine yields Fri 03/13/2020 which completely breaks your code.

You should be using FOR /F with WMIC OS GET LOCALDATETIME to get the date and/or time in a way that can be parsed reliably. There is another WMIC option to get the various date/time components separately, but I cannot remember off the top of my head.

I would like to know if that's Windows 10 that you are using or one of the deprecated versions: Windows 8.1, Windows 8, Windows 7, Windows vista, Windows xp?
I'm kind of aware of this, but it is great that you pointed out. If the problem with date representation appears on Windows 10 I might consider WMIC.
However for simplicity I would like to keep using this method of gathering Date from operating system.
Not to mention that this is a port from Bash script to Batch script. I would like to keep both looking similarly for cross-platform readability if that's possible.

Your SET /A arithmetic will fail when you get a number like 08 or 09 because 0 prefixed values are treated as octal notation. A simple solution is to prefix the value with 1 and then subtract 100.
For example:

Code: Select all

set month=09
set /a "PrevMonth=1%month%-100"

Dave Benham

Now this is really great observation, would have not though about this until it has been too late.

Thanks Dave, will try to implement these changes tomorrow.

[dbenham]

Your way of dealing with dates is not good as it depends on the locale settings for the computer. For example, %date% on my machine yields Fri 03/13/2020 which completely breaks your code.

You should be using FOR /F with WMIC OS GET LOCALDATETIME to get the date and/or time in a way that can be parsed reliably. There is another WMIC option to get the various date/time components separately, but I cannot remember off the top of my head.

I would like to know if that's Windows 10 that you are using or one of the deprecated versions: Windows 8.1, Windows 8, Windows 7, Windows vista, Windows xp?
I'm kind of aware of this, but it is great that you pointed out. If the problem with date representation appears on Windows 10 I might consider WMIC.
However for simplicity I would like to keep using this method of gathering Date from operating system.
Not to mention that this is a port from Bash script to Batch script. I would like to keep both looking similarly for cross-platform readability if that's possible.

The issue most definitely is persistent across all versions of Windows - All versions of Windows have configuration settings to control the format of %DATE% for different locales.

WMIC is universally available to all versions of Windows from Vista onward. Some versions of XP do not have WMIC, but hopefully you are not still dealing with machines that are still on XP, given that it has not been supported since April 2014.


Dave Benham

[Squashman]

Windows 8 is not deprecated.

[BoQsc]

Windows 8 is not deprecated.

Windows 8
Unsupported as of January 12, 2016
https://en.wikipedia.org/wiki/Windows_8

Windows 8.1
Mainstream support ended on January 9, 2018
Extended support until January 10, 2023
Upgrading to Windows 8.1 is required for Windows 8 users to receive updates and support after January 12, 2016[4]
https://en.wikipedia.org/wiki/Windows_8.1

Officialy might be deprecated in 3 years. I consider them already deprecated. Since all the encouragement is towards windows 10.
https://en.wikipedia.org/wiki/Deprecation

[BoQsc]

Your way of dealing with dates is not good as it depends on the locale settings for the computer. For example, %date% on my machine yields Fri 03/13/2020 which completely breaks your code.

You should be using FOR /F with WMIC OS GET LOCALDATETIME to get the date and/or time in a way that can be parsed reliably. There is another WMIC option to get the various date/time components separately, but I cannot remember off the top of my head.

This one should resolve both octal notation problem and inconsistencies of parsing date across different Windows versions.
I'm sharing to make sure I'm not missing something.

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@echo off
SETLOCAL EnableDelayedExpansion

FOR /F "skip=1 tokens=1-6" %%A IN ('WMIC Path Win32_LocalTime Get Day^,Hour^,Minute^,Month^,Second^,Year /Format:table') DO (
    SET "YEAR=!YEAR!%%F"
    SET "MONTH=!MONTH!%%D"
    SET "DAY=!DAY!%%A"

 )


echo YEAR %YEAR% 
echo MONTH %MONTH% 
echo DAY %DAY% 

Output:

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YEAR 2020
MONTH 3
DAY 14

[BoQsc]

And here the main script with the new method of gathering date from operating system: Seems to be working pretty well.

Code: Select all

@ECHO OFF
SETLOCAL EnableDelayedExpansion

REM Get current Year and Month for Windows 10 Windows 8.1 Windows 8 Windows 7
FOR /F "skip=1 tokens=1-6" %%A IN ('WMIC Path Win32_LocalTime Get Day^,Hour^,Minute^,Month^,Second^,Year /Format:table') DO (
    SET "year_now=!year_now!%%F"
    SET "month_now=!month_now!%%D"

 )
SET "year_now=%year_now:~2,2%"


SET "releaseCycle=Interim";
IF "%releaseCycle%"=="LTS" (
	echo "Haven't been implemented";
) ELSE IF "%releaseCycle%"=="Interim" (
	IF %month_now% LSS 4 (
		SET /A "year=!year_now! - 1"
		SET "release_version=!year!.10"
		echo !release_version!;
	)
	IF %month_now% LSS 10 (
		IF %month_now% GEQ 04 (
			SET "release_version=!year_now!.04"
			echo !release_version!;
		)
	)
	IF %month_now% GEQ  10 (
		SET "release_version=!year_now!.10"
		echo !release_version!;
	)
) ELSE IF "%releaseCycle%"=="Daily" (
	echo "Haven't been implemented";
) ELSE (
	echo "Haven't been implemented";
)
pause

Code: Select all

19.10;
Press any key to continue . . .