# Documentation for accepted conditionals syntax in logstash filter
**URL:** https://discuss.elastic.co/t/documentation-for-accepted-conditionals-syntax-in-logstash-filter/68736
**Category:** Logstash
**Created:** [December 12, 2016, 4:28pm UTC](https://discuss.elastic.co/t/documentation-for-accepted-conditionals-syntax-in-logstash-filter/68736 "2016-12-12T16:28:35Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@valugi](https://discuss.elastic.co/u/valugi)
#### Post date: [December 12, 2016, 4:28pm UTC](https://discuss.elastic.co/t/documentation-for-accepted-conditionals-syntax-in-logstash-filter/68736/1 "2016-12-12T16:28:35Z")
I failed to find the full documentation on how to use conditionals inside filter block. Is this syntax valid:
```
filter {
if [tags] == "A" and [tags] == "B" {
grok {
....
}
}
```
or should I use `if "A" in [tags]`. Logstash does not mind the first but does not produces the desired outcome either.
Thanks
---
### Author:  [@valugi](https://discuss.elastic.co/u/valugi)
#### Post date: [December 12, 2016, 4:45pm UTC](https://discuss.elastic.co/t/documentation-for-accepted-conditionals-syntax-in-logstash-filter/68736/2 "2016-12-12T16:45:52Z")
Found it: [https://www.elastic.co/guide/en/logstash/current/event-dependent-configuration.html#conditionals](https://www.elastic.co/guide/en/logstash/current/event-dependent-configuration.html#conditionals)
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 9, 2017, 4:46pm UTC](https://discuss.elastic.co/t/documentation-for-accepted-conditionals-syntax-in-logstash-filter/68736/3 "2017-01-09T16:46:02Z")
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