# Problem with script in transform accessing an array
**URL:** https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043
**Category:** Elasticsearch
**Tags:** elastic-stack-alerting
**Created:** [June 21, 2015, 8:24am UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043 "2015-06-21T08:24:24Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@jettro](https://discuss.elastic.co/u/jettro)
#### Post date: [June 21, 2015, 8:24am UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/1 "2015-06-21T08:24:24Z")
Hi, I want to return the length of an array in a transform script within the logging action. I am doing this:
```
"actions": {
"log": {
"transform": {
"script": "return [total_snapshots : ctx.payload.snapshots.length]"
},
"logging": {
"text": "Found {{ctx.payload.total_snapshots}} snapshots at {{ctx.execution_time}}"
}
}
}
```
I can get back an array of objects using ct..payloaad.snapshots.snapshot but I want to have the length of the array. Does someone know whether this is possible and how?
Thanks.
---
### Author:  [@jettro](https://discuss.elastic.co/u/jettro)
#### Post date: [June 21, 2015, 8:50pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/2 "2015-06-21T20:50:04Z")
I found the way to make this work, can't stop thinking I must have tried this before. Still it does work now with the following code:
```
"actions": {
"log": {
"transform": {
"script": "return [total_snapshots : ctx.payload.snapshots.size()]"
},
"logging": {
"text": "Found {{ctx.payload.total_snapshots}} snapshots at {{ctx.execution_time}}"
}
}
}
```
---
### Author:  [@skearns](https://discuss.elastic.co/u/skearns)
#### Post date: [June 21, 2015, 9:02pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/3 "2015-06-21T21:02:54Z")
Hi Jettro,
I'm glad you figured it out! Thanks for sharing the working solution 😄
---
### Author:  [@uboness](https://discuss.elastic.co/u/uboness)
#### Post date: [June 24, 2015, 5:09pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/4 "2015-06-24T17:09:18Z")
Jettro, looks like `snapshots` is not an array, but a list? Is it by any chance coming from a json payload? for real "arrays" `.length` should indeed work (as well as `size()`)
---
### Author:  [@jettro](https://discuss.elastic.co/u/jettro)
#### Post date: [June 24, 2015, 8:40pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/5 "2015-06-24T20:40:00Z")
The payload is coming from this response, it looks line an array to me in Json. Not sure what groovy does with it though. From the jsonslurper documentation I read they convert arrays to lists. In that case what you're saying @url sounds like the reason. It is a List not and array.
```
{
"snapshots": [
{
"snapshot": "conferences-20150619094018", //removed other fields
},
{
"snapshot": "conferences-20150619113941",
},
{
"snapshot": "conferences-20150621223930",
},
{
"snapshot": "conferences-20150621224116",
}
]
}
```
---
### Author:  [@uboness](https://discuss.elastic.co/u/uboness)
#### Post date: [June 24, 2015, 11:09pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/6 "2015-06-24T23:09:31Z")
so if it's coming from json, then actually its watcher that converts the json arrays to lists :)... I just wasn't sure where you're gettings `snapshots` from (it could have been from a script transform)
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 1:49pm UTC](https://discuss.elastic.co/t/problem-with-script-in-transform-accessing-an-array/24043/7 "2017-07-06T13:49:25Z")