Feature request: How many authors?

[mornington]

Is there any way to count the number of items in a comma-separated field, such as the list of authors?

Basically, I'm after creating a custom column which contains a count of the number of authors for each book (to make life easier when it comes to manually cross-linking books into different collections on the kindle, since you ask). But for the life of me I can't see an {authors_count} or (authors:count()} or similar.

[itimpi]

First time I can ever remember any asking about such a feature

You should raise the feature request by raising a ticket in the Calibre tracking system as forum messages for feature requests can get lost (and then forgotten) amongst the volume of messages posted.

[mornington]

Cheers. I've raised a ticket here:

http://bugs.calibre-ebook.com/ticket/7769

[chaley]

Code submitted.

There is now a template function 'count'. It takes one argument, the character that separates the items in the list. Most lists use comma, but authors uses ampersand.

Examples:
tags: {tags:count(,)}
authors: {authors:count(&)}
a custom multiple field: {#mymult:count(,)}

As another example, imagine that you have a custom field #genre that you use for hierarchical tagging. This would be a text (non-multiple) field containing things like
Science:Biology:Plankton
Fiction:Mystery:Crime:Police
You can count these via
{#genre:count(:)}

[mornington]

Wonderful. Thanks muchly for that - it'll come in very useful (especially the way you've implemented it).

Presumably this will show up in the next release?

[chaley]

Originally Posted by mornington

Presumably this will show up in the next release?

Probably. Real answer depends on how much available 'review code' time Kovid has available.

[mornington]

I'm sure it'll show up sometime ;-)

And thanks again for writing this.

[mornington]

And I see it's appeared in release 0.7.32.

One small issue. though, is that the "number" produced by count() seems to be treated as text, rather than an integer, for sorting purposes meaning that "{authors:count(&)}" can't be sorted numerically.

This can be worked around by using a second custom column with "{#numauthors:0>2s}" but is there any way to have the whole thing done in a single field (i.e. so the output is "01","02,"03",etc) or to make the numbers in such a column be sorted as numbers, rather than as text?

[mornington]

Originally Posted by mornington

And I see it's appeared in release 0.7.32.

One small issue. though, is that the "number" produced by count() seems to be treated as text, rather than an integer, for sorting purposes meaning that "{authors:count(&)}" can't be sorted numerically.

This can be worked around by using a second custom column with "{#numauthors:0>2s}" but is there any way to have the whole thing done in a single field (i.e. so the output is "01","02,"03",etc) or to make the numbers in such a column be sorted as numbers, rather than as text?

As a more general principle, I suppose I'm asking if there's a way to tell calibre that a given custom column should be sorted as numerical rather than textual data.

[chaley]

Originally Posted by mornington

And I see it's appeared in release 0.7.32.

One small issue. though, is that the "number" produced by count() seems to be treated as text, rather than an integer, for sorting purposes meaning that "{authors:count(&)}" can't be sorted numerically.

This can be worked around by using a second custom column with "{#numauthors:0>2s}" but is there any way to have the whole thing done in a single field (i.e. so the output is "01","02,"03",etc) or to make the numbers in such a column be sorted as numbers, rather than as text?

I assume you have created a composite custom column showing this value? If you want leading zeros, then that column's template should be

{authors:0>2s:count(&)}

Format specifications are applied after function specifications.

As for specifying the sort type, that won't work in your case. Composite columns are always strings.

[mornington]

Originally Posted by chaley

I assume you have created a composite custom column showing this value? If you want leading zeros, then that column's template should be

{authors:0>2s:count(&)}

Format specifications are applied after function specifications.

As for specifying the sort type, that won't work in your case. Composite columns are always strings.

That's what I was after - thanks a lot. I tried a couple of different syntax combinations (but not that one, obviously) but couldn't figure out one that did it.

Sorting-wise, it's fine sorting by string so long as the string is zero-filled ;-)