# Correct way to access nested fields in logstash filters
**URL:** https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005
**Category:** Logstash
**Created:** [May 23, 2018, 2:31pm UTC](https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005 "2018-05-23T14:31:08Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@leandrojmp](https://discuss.elastic.co/u/leandrojmp)
#### Post date: [May 23, 2018, 2:31pm UTC](https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005/1 "2018-05-23T14:31:09Z")
Hello,
The documentation says that to access nested fields you need to use the format `[parent][child]`, but the format `[parent.child]` also works.
I started to use `[parent.child]` after some tests on version `5.4` where, for some reason maybe not related to the field name, the format `[parent][child]` was not working.
Now I have a few fields and filters where I use `[parent.child]` without any problem.
My question is: Should I change it to `[parent][child]` or could I keep using `[parent.child]`, which looks better in my opinion
A example of my use is:
```auto
if [device.model] == "MODEL" {
translate {
field => "rule.policy"
destination => "rule.policy"
override => true
dictionary_path => ["/etc/logstash/dict/dict-rules.yml"]
refresh_interval => "900"
}
}
```
If I change it to `[parent][child]` as show bellow, it will work without any problem?
```auto
if [device][model] == "MODEL" {
translate {
field => "[rule][policy]"
destination => "[rule][policy]"
override => true
dictionary_path => ["/etc/logstash/dict/dict-rules.yml"]
refresh_interval => "900"
}
}
```
---
### Author:  [@leandrojmp](https://discuss.elastic.co/u/leandrojmp)
#### Post date: [May 23, 2018, 3:57pm UTC](https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005/2 "2018-05-23T15:57:01Z")
Oh, I've just made a confusion.
The fields aren't really nested, they are objects, that's why the [parent][child] did not worked when I tried, the field name was parent.child.
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [May 23, 2018, 4:06pm UTC](https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005/3 "2018-05-23T16:06:42Z")
> [@leandrojmp](#):
>
> the field name was parent.child
Having . in a field name works, except where it does not work (and there are definitely places where it doesn't). I believe it is unsupported.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [June 20, 2018, 4:06pm UTC](https://discuss.elastic.co/t/correct-way-to-access-nested-fields-in-logstash-filters/133005/4 "2018-06-20T16:06:45Z")
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