# Detect empty array

**URL:** <https://discuss.elastic.co/t/detect-empty-array/158801>\
**Category:** Logstash\
**Created:** [November 29, 2018, 4:56pm UTC](https://discuss.elastic.co/t/detect-empty-array/158801 "2018-11-29T16:56:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Shawcs](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/shawcs/32/45490_2.png) [@Shawcs](https://discuss.elastic.co/u/Shawcs)\
**Post date:** [November 29, 2018, 4:56pm UTC](https://discuss.elastic.co/t/detect-empty-array/158801/1 "2018-11-29T16:56:33Z")

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Hi,

how could I detect when an array in a json is empty with logstash ?

example:

- EMPTY

- FULL:

---

<div class="post-metadata">

**Author:** ![guyboertje](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/guyboertje/32/31592_2.png) [@guyboertje](https://discuss.elastic.co/u/guyboertje)\
**Post date:** [December 7, 2018, 10:54am UTC](https://discuss.elastic.co/t/detect-empty-array/158801/2 "2018-12-07T10:54:36Z")

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```auto
if [serviceContexts] and [serviceContexts][0] {
  # array has at least one element
} else {
  # array has no elements
}

```

---

<div class="post-metadata">

**Author:** ![Shawcs](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/shawcs/32/45490_2.png) [@Shawcs](https://discuss.elastic.co/u/Shawcs)\
**Post date:** [December 7, 2018, 1:59pm UTC](https://discuss.elastic.co/t/detect-empty-array/158801/3 "2018-12-07T13:59:53Z")

</div>

Yes this is what I come up with. Wasn't sure if that was the best way to do it.

Thanks

---

<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:** [January 4, 2019, 1:59pm UTC](https://discuss.elastic.co/t/detect-empty-array/158801/4 "2019-01-04T13:59:58Z")

</div>

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