flask & jinja2 & 0 & None

Question

This is a pretty routine thing I do:

{{ data['key'] or '' }} so it won't display None, but it also won't display a 0 and sometimes-- most of the time-- I really need 0 values to show, but never a None.

What's the easiest fix for this? Something like {{ data['key']|none('') }} where none is a filter returning a blank if the value is None?

Or something checking for a non-None value inside the {{ ... }} tags? What's your quick fix here?

r-m-n · Answer 1 · 2015-10-11T17:30:59.693

2

{{ data['key'] if data['key']!=None else '' }}

edited Oct 11 '15 at 17:30

answered Oct 11 '15 at 17:25

r-m-n

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yeah.. that'll do, just not as clean as the old `or ''` – Wells Oct 11 '15 at 17:27
you can add `else ' '` – r-m-n Oct 11 '15 at 17:32
`is not None` is the canonical way. `is`/`is not` compares by identity (=memory address) rather than by value, and there's only one `None` object. – ivan_pozdeev Oct 11 '15 at 18:03

flask & jinja2 & 0 & None

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