How to negate test in jinja2

Question

I can filter a list in jinja using selectattr, for example if I want the elements for which foo is None:

lists | selectattr('foo','none')

but how can I negate this? How can I get all elements for which foo is not none?

Answer 1

{{ lists | rejectattr('foo', 'none') }}

http://jinja.pocoo.org/docs/dev/templates/#rejectattr