# Contrib -- UI small discovery: negation operator

**URL:** <https://forum.genieacs.com/t/contrib-ui-small-discovery-negation-operator/2852>\
**Category:** Uncategorized\
**Created:** [August 11, 2022, 2:43pm UTC](https://forum.genieacs.com/t/contrib-ui-small-discovery-negation-operator/2852 "2022-08-11T14:43:24Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![rudymartin](https://avatars.discourse-cdn.com/v4/letter/r/919ad9/32.png) [@rudymartin](https://forum.genieacs.com/u/rudymartin)\
**Post date:** [August 11, 2022, 2:43pm UTC](https://forum.genieacs.com/t/contrib-ui-small-discovery-negation-operator/2852/1 "2022-08-11T14:43:24Z")

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this is probably documented in the source code but I could not find references at the forum search tool nor google search.

Scenario: we implementing a change in Wifi configuration on all CPEs. Each CPE with the change gets tagged, so I wanted to get the list of devices which still have to be configured.

As usual it was by accident, while filtering devices by two tags at the same time, I took notice of the AND operator at the url.

So I replaced it by:

**NOT Q(“Tag”, “falta”)**

which brought the list of devices without the tag **falta**.

It also works with other kind of filters. In our case we also had “SW Version” (software version) which is added in the config page.