Unset vs Undefined

ownedbycats · 03-06-2021, 06:20 PM

For a column icon rule/saved search, is there any way to differentiate between an integer column value that has been deliberately set as "undefined" from one that has not been set at all?

I want to show an icon/make a search for books missing a value in #chaptercount, but a lot of books don't really have traditional chapters.

I thought about just putting '0' in for those books, but that would appear in the book details and break the math if I want to divide pagecount by chaptercount or something.

chaley · 03-06-2021, 07:02 PM

Yes, with a GPM template. The following example shows you how to do the test. Up to you to figure out what you want to do in each case.

Code:

program: 
	x = raw_field('#myint');
	if x == 'None' then
		'Not Set'
	else
		strcat('Is Set to ', x)
	fi

In the latest calibre release, raw_field() takes an optional second parameter specifying what to return if the field isn't defined. Example:

Code:

	x = raw_field('#myint', -999);

Regarding searching, you can distinguish between the two by looking for 'true' or 'false' as in

Code:

#myint:true

chaley · 03-07-2021, 07:23 AM

Actually, for rules you don't need the GPM template. You can instead use a double condition, one checking that the value is set and the other checking the actual value.

03-06-2021, 06:20 PM	#1
ownedbycats Custom User Title Posts: 11,386 Karma: 79699999 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	Unset vs Undefined For a column icon rule/saved search, is there any way to differentiate between an integer column value that has been deliberately set as "undefined" from one that has not been set at all? I want to show an icon/make a search for books missing a value in #chaptercount, but a lot of books don't really have traditional chapters. I thought about just putting '0' in for those books, but that would appear in the book details and break the math if I want to divide pagecount by chaptercount or something. Last edited by ownedbycats; 03-06-2021 at 06:49 PM.

03-06-2021, 07:02 PM	#2
chaley Grand Sorcerer Posts: 12,529 Karma: 8074628 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Yes, with a GPM template. The following example shows you how to do the test. Up to you to figure out what you want to do in each case. Code: program: x = raw_field('#myint'); if x == 'None' then 'Not Set' else strcat('Is Set to ', x) fi In the latest calibre release, raw_field() takes an optional second parameter specifying what to return if the field isn't defined. Example: Code: x = raw_field('#myint', -999); Regarding searching, you can distinguish between the two by looking for 'true' or 'false' as in Code: #myint:true Last edited by chaley; 03-06-2021 at 07:04 PM.

03-07-2021, 07:23 AM	#3
chaley Grand Sorcerer Posts: 12,529 Karma: 8074628 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Actually, for rules you don't need the GPM template. You can instead use a double condition, one checking that the value is set and the other checking the actual value. Attached Thumbnails

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