Custom column: "pubdate" and "ifempty"

[StillReading]

I've been using code like "{languages:ifempty(-)}" in a custom combined column successfully. I've been trying a similar approach for a custom formatted "pubdate", but I can't figure out the correct syntax. Could someone give me a simple example please? I'm not a "real" coder, so the Calibre manual is much too complicated for me... I'd like to have the pubdate formatted as "MMM yyyy", with a "-" character if the field is empty (= no pubdate set). Date formatting works fine ("{:'format_date(raw_field('pubdate'),'yyyy')'} "), and "ifempty" works fine, too - I just don't know how to combine the functions properly.

EDIT: solved the problem by creating another custom column which stores the formatted pubdate. I'd still be interested in knowing if there's a way to get the formatted date without using an additional column.

[chaley]

I think that this template does what you want:

{:'ifempty(format_date(raw_field('pubdate'),'yyyy'), '-')'}

[StillReading]

Thanks, that works beautifully! I've played around a bit with the "{fieldname:|Prefix|Suffix}" syntax and tried to combine that approach with your example, but couldn't get it working properly. Best I got was the formatted pubdate, directly followed by the "raw" pubdate value. I think this is because of improper quoting (I've tried various combinations), or maybe it's not possible to combine two functions.

For anyone playing around with combined fields: I found that if you let Calibre display a combined field as a column in the "grid view", and single click on a row in that column (just like you would when you'd wanted to edit a value), Calibre lets you edit the function directly with a live preview of the result (!). I don't think that functionality is explained in the manual, it's very helpful when playing around with functions.

[chaley]

Originally Posted by StillReading

Thanks, that works beautifully! I've played around a bit with the "{fieldname:|Prefix|Suffix}" syntax and tried to combine that approach with your example, but couldn't get it working properly. Best I got was the formatted pubdate, directly followed by the "raw" pubdate value. I think this is because of improper quoting (I've tried various combinations), or maybe it's not possible to combine two functions.

Without knowing what you tried and what you want to do it is hard to say much. It is very possible that what you want to do is doable only in general program mode, which allows arbitrary function nesting.

For anyone playing around with combined fields: I found that if you let Calibre display a combined field as a column in the "grid view", and single click on a row in that column (just like you would when you'd wanted to edit a value), Calibre lets you edit the function directly with a live preview of the result (!). I don't think that functionality is explained in the manual, it's very helpful when playing around with functions.

You can do this without creating a column by using the Template tester. I added it to the context menu for "books in the library" so I can open it on any book with a right-click.