Templates: various questions not worth their own thread

[ownedbycats]

Out of curiosity, is Action Chains single-field edit the only method for updating a non-composite field from a template?

[chaley]

Originally Posted by ownedbycats

Out of curiosity, is Action Chains single-field edit the only method for updating a non-composite field from a template?

No, although it might be the best option depending on what sort of changes you are making. You can use Edit Metadata Bulk S&R with the source as a template. If you are brave you can the template tester with Python templates, although you will need to tell the GUI about the changes -- reseting the tag browser, cleaning up user categories, and refreshing the book list.

[ownedbycats]

Search & Replace sounds more useful for one-off edits, and Action Chains for using it on a semi-regular basis

[ownedbycats]

Originally Posted by ownedbycats

Search & Replace sounds more useful for one-off edits, and Action Chains for using it on a semi-regular basis

Well, unless the field (series_index) isn't available for editing with the SFE.

When using an if-then in S&R should I need to add an 'else $columnname' to return the original value to prevent nulling it out?

EDIT: It looks so.

[chaley]

Originally Posted by ownedbycats

When using an if-then in S&R should I need to add an 'else $columnname' to return the original value to prevent nulling it out?

EDIT: It looks so.

The field will be replaced with whatever the template returns. Even if it is replacing it with itself.

[chaley]

Originally Posted by ownedbycats

Well, unless the field (series_index) isn't available for editing with the SFE.

This stored template sets the series index to whatever the argument is:

python:
def evaluate(book, context):
	args = context.arguments
	if args is None or len(args) != 1:
		return 'Invalid arguments'
	try:
		sidx = float(args[0])
	except:
		return 'Bad series index'
	db = context.db
	from calibre.gui2.ui import get_gui
	gui = get_gui()

	bids = gui.current_view().get_selected_ids()
	results = []
	for bid in bids:
		db.set_series_index(bid, sidx)
		results.append(db.title(bid, index_is_id=True))
	db.refresh_ids(bids)
	gui.current_view().model().refresh_ids(bids)
	return 'Done: ' + ', '.join(results)

You call it by selecting books and running this template in the template tester:

program: change_series_index(0)

where the 0 is whatever you want.

You can also use it in an Action Chains formula action.

You can't use it in bulk edit search & replace.

[ownedbycats]

I just put program: columnupdate_seriesindex(0) in the template tester and it worked. The downside is I was testing with a book I hadn't wanted to change to 0. Oh well.

For future reference, can other called python templates update columns directly without the action chain?

Additionally: Other than the formulas action, would it work if called in a SFE template mode? That way I could do an if-then.

[chaley]

Originally Posted by ownedbycats

I just put program: columnupdate_seriesindex(0) in the template tester and it worked. The downside is I was testing with a book I hadn't wanted to change to 0. Oh well.

Yea, that is what the template does. I didn't add a "test" mode.

For future reference, can other called python templates update columns directly without the action chain?

Yes. However, depending on what you do you might need to do more work to update the GUI. For example, if you change a tag's name then you must update the tag browser and all the books affected by the rename. This isn't hard but it must be done.

Additionally: Other than the formulas action, would it work if called in a SFE template mode? That way I could do an if-then.

Not as written because it operates on the entire selection. IIRC SFE is called per book, so if the template was changed to work on the current book then it should work. Two possible problems:

• The GUI will be updated on every call so there might be some screen flashing. If SFE takes care of updating the GUI then those bits can be removed from the template.
• SFE doesn't know how to update the series_index, so the template would do that behind its back. I don't know whether that will work reliably.

You could of course put the if/then in the Formula template that calls the python template. It would evaluate whether or not to call the stored template.

[ownedbycats]

Oh yeah, my brain skipped a few steps "wait, that's why I wasn't using SFE in the first place...". Formulas I'll try that, not as familiar with using them.

[ownedbycats]

I have this template for a composite column used for sorting in one VL/view manager view.

program:
## This one checks that #kobostatus has a value. If it does, return 'no' if it matches two specific criteria, and 'yes' otherwise.
	if 
		$#kobostatus
	then 
		switch_if(
			'\[(Add|Send) to Device\]' in $#kobostatus, 'No',
			$#kobostatus=='[Kobo Store]' && !$#kobodate, 'No',
		 	'Yes'
		)		
	fi

Functionally, this should do the same thing:

program: 
## This returns an empty if #kobostatus doesn't have a value. Other lines are unaffected.
	switch_if(
		!$#kobostatus, '',
## Alternate: $#kobostatus=='',
		'\[(Add|Send) to Device\]' in $#kobostatus, 'No',
		$#kobostatus=='[Kobo Store]' && !$#kobodate, 'No',
	 	'Yes'
	)

Would either of them be particularly faster?

[chaley]

Originally Posted by ownedbycats

Would either of them be particularly faster?

No. Both need to do the test of $#kobostatus. Whether that is in an if or a switch_if might make a difference of nanoseconds one way or the other, which is way below what I worry about.

[ownedbycats]

I'll keep the original, then, as it makes a bit more sense to me. Thanks

[ownedbycats]

For a formula for various book statistics: is there a function similar to round, but rounding to a certain number of decimal points instead of a whole number?

EDIT: format_number works. New question: How do I add a line break? This returns as one long line.

program:
strcat(
	'Chapter Count:', $#chaptercount,
	'Page Count:', $#pagecount,
	'Average Pages per Chapter:', format_number((divide($#pagecount, $#chaptercount)), '{0:5.2f}')
	)

[chaley]

Originally Posted by ownedbycats

For a formula for various book statistics: is there a function similar to round, but rounding to a certain number of decimal points instead of a whole number?

EDIT: format_number works. New question: How do I add a line break? This returns as one long line.

program:
strcat(
	'Chapter Count:', $#chaptercount,
	'Page Count:', $#pagecount,
	'Average Pages per Chapter:', format_number((divide($#pagecount, $#chaptercount)), '{0:5.2f}')
	)

Use the character() function, specifically character('newline')

[ownedbycats]

That works, thanks