[chaley]

Originally Posted by kjdavies

How about

program:
    '.'.join(filter(None, ($#titlecount,$#pagecount,$series,$#pubseries,$#pubseries_index)))

? I think this should make a string concatenating only the non-None values in the list, and prevent leading or trailing '.'.

Problem: that intermixes python and the GPR template language. The template should be rewritten as

python:
def evaluate(book, context):
    vals = (filter(
                None, 
                (
                    book.get('#myint2'), 
                    book.get('#pagecount'), 
                    book.get('series'), 
                    book.get('#series'),
                    book.get('#series_index')))
                )
    vals = ((str(v) if isinstance(v, (int, float)) else v) for v in vals)
    return '.'.join(vals)

Note: the list_join() template function ignores empty values, not adding them to the result list. None won't be encountered unless you use raw_field() or $$#.