# Add an array in an array

**URL:** <https://discuss.elastic.co/t/add-an-array-in-an-array/118901>\
**Category:** Logstash\
**Created:** [February 7, 2018, 6:33pm UTC](https://discuss.elastic.co/t/add-an-array-in-an-array/118901 "2018-02-07T18:33:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![uderline](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/uderline/32/26245_2.png) [@uderline](https://discuss.elastic.co/u/uderline)\
**Post date:** [February 7, 2018, 6:33pm UTC](https://discuss.elastic.co/t/add-an-array-in-an-array/118901/1 "2018-02-07T18:33:12Z")

</div>

Hello !

I'm working with the 5.6 elastic stack.  
I would like to be able to include an array in an array when doing a `add_field` using Logstash.

```
mutate {
	add_field => {
		"weight" => [[0.4, 0.6], [0.3, 0.8], [0.6, 0.95] ]
	}
}

```

The problem is that Logstash considers each entry as a string and I need it to be an array with floats.

```
"weight" => [
    [0] "[0.4, 0.6]",
    [1] "[0.3, 0.8]",
    [2] "[0.6, 0.95]"
]

```

I thought of converting _weight_ into a float property - just in case - but then `weight = 0.0`.

How can I avoid the string conversion and keep float values ?

Regards,

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [February 28, 2018, 6:57pm UTC](https://discuss.elastic.co/t/add-an-array-in-an-array/118901/2 "2018-02-28T18:57:49Z")

</div>

Logstash's configuration language is too limited for that. You'll have to use a ruby filter.

---

<div class="post-metadata">

**Author:** ![uderline](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/uderline/32/26245_2.png) [@uderline](https://discuss.elastic.co/u/uderline)\
**Post date:** [March 1, 2018, 4:29pm UTC](https://discuss.elastic.co/t/add-an-array-in-an-array/118901/3 "2018-03-01T16:29:37Z")

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Thanks for the reply that confirms what I thought.

My knowledge in Ruby is quite rudimentary so I decided to change my ingest elastic plugin for it to cast the "String array" to a Java List.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [March 29, 2018, 4:29pm UTC](https://discuss.elastic.co/t/add-an-array-in-an-array/118901/4 "2018-03-29T16:29:40Z")

</div>

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