# Using Arrays in Logstash

**URL:** <https://discuss.elastic.co/t/using-arrays-in-logstash/57434>\
**Category:** Logstash\
**Created:** [August 8, 2016, 1:51am UTC](https://discuss.elastic.co/t/using-arrays-in-logstash/57434 "2016-08-08T01:51:14Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![elad\_sheinfeld](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/elad_sheinfeld/32/91900_2.png) [@elad\_sheinfeld](https://discuss.elastic.co/u/elad_sheinfeld)\
**Post date:** [August 8, 2016, 1:51am UTC](https://discuss.elastic.co/t/using-arrays-in-logstash/57434/1 "2016-08-08T01:51:14Z")

</div>

Hi All,  
I've got a field which represents a list of destinations, represented by a decimal values  
I now need to "translate" each of those destinations to their IP equivalent.  
I'm trying to use the following code:

```
ruby {	init => " '[DestDec][]'
					'[DestIP][]'"
		code => " DestDec.each{|x| event['[DestIP][x]'] = event['[DestDec][x]'].to_i].pack('N').unpack('C4').join('.')}"
	}

```

but I'm getting a Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::DestDec.

what am I doing wrong?  
how do I initialize an array?

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<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:** [August 10, 2016, 5:49am UTC](https://discuss.elastic.co/t/using-arrays-in-logstash/57434/2 "2016-08-10T05:49:09Z")

</div>

What is `[DestDec][]` and `[DestIP][]` supposed to mean? It doesn't look like valid Ruby code. What does the original event look like and what do you want to transform it to?

---

<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:** [July 6, 2017, 4:44am UTC](https://discuss.elastic.co/t/using-arrays-in-logstash/57434/3 "2017-07-06T04:44:10Z")

</div>

Closed on July 6, 2017, 4:44am UTC