# \[FEATURE\] Add ability to 'lookup' in arrays and objects in expression language

**URL:** <https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280>\
**Category:** Ignition\
**Tags:** perspective\
**Created:** [June 2, 2022, 2:01am UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280 "2022-06-02T02:01:25Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [June 2, 2022, 2:01am UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/1 "2022-06-02T02:01:25Z")

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With the advent of Perspective, array and object property types are used extensively, however there’s no way to really use these in the expression language e.g. to lookup a value within an array or an object and return the found value.

Can new expression functions be added, or can existing ones be modified to allow this? (e.g. `lookup`)

Vote here:

> **[Add ability to 'lookup' in arrays and objects in expression language | Voters...](https://ideas.inductiveautomation.com/ignition-features-and-ideas/p/add-ability-to-lookup-in-arrays-and-objects-in-expression-language)**

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [June 2, 2022, 2:28pm UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/2 "2022-06-02T14:28:48Z")

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`indexOf` and ‘slicing’ syntax should work. It’s not as elegant as `lookup`, but there was some reason I didn’t add support for `lookup` when I implemented this for other expression functions I no longer remember.

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**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [June 3, 2022, 1:26am UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/3 "2022-06-03T01:26:25Z")

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> [@paul-griffith](#):
>
> `indexOf` and ‘slicing’ syntax should work

Hmm, I tried some things and I'm not sure how to use slicing here? ☹ the expression language doesn't seem to see the array as an array, even something like `a[0]` or `a[0,0]` doesn't work where `a` is an array

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [June 3, 2022, 4:29pm UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/4 "2022-06-03T16:29:26Z")

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![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/5/6541ec4294bbf5717d80966c40c0bc40ff2104ab.png)

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<div class="post-metadata">

**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [June 3, 2022, 11:04pm UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/5 "2022-06-03T23:04:17Z")

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That’s exactly what I tried I think it was in 8.1.5 though. Was that added more recently? Regardless though, I don’t think that helps to find an item in the array, or does it?

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [June 3, 2022, 11:21pm UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/6 "2022-06-03T23:21:25Z")

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8.1.8 or higher:  
[https://docs.inductiveautomation.com/display/DOC81/New+in+this+Version#NewinthisVersion-Expressions.1](https://docs.inductiveautomation.com/display/DOC81/New+in+this+Version#NewinthisVersion-Expressions.1)

Gotta get that upgrade done 🙂

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<div class="post-metadata">

**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [June 3, 2022, 11:25pm UTC](https://forum.inductiveautomation.com/t/feature-add-ability-to-lookup-in-arrays-and-objects-in-expression-language/60280/7 "2022-06-03T23:25:38Z")

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Sigh ☹ it’s happening in 2 3? weeks. I won’t know what to do without myself once it’s done 😁