# Indirect Tagging in Expression **URL:** \ **Category:** Ignition\ **Tags:** ignition81, perspective, scripting\ **Created:** [March 4, 2024, 4:04pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771 "2024-03-04T16:04:30Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Soham\_Ambekar](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@Soham\_Ambekar](https://forum.inductiveautomation.com/u/Soham_Ambekar)\ **Post date:** [March 4, 2024, 4:04pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/1 "2024-03-04T16:04:30Z")
I am trying to concatenate two string values by indirect method in scripting. e.g. i have written this in expression section `concat({[SBR]Seed Receiving/{view.params.AI}/Gross Value.value}, {[SBR]Seed Receiving/{view.params.AI}/Gross Unit.value})` where I have passed AI in the params section of my container How can I do it any idea? ![1](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/6/e68173545af92320551473e3b5bd7837da2580d2.png) ---
**Author:** ![leonardo.godoi](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/leonardo.godoi/32/27178_2.png) [@leonardo.godoi](https://forum.inductiveautomation.com/u/leonardo.godoi)\ **Post date:** [March 4, 2024, 4:09pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/2 "2024-03-04T16:09:17Z")
Try: ```auto tag("[SBR]Seed Receiving/"+ {view.params.AI} + "/Gross Value") + tag("[SBR]Seed Receiving/"+ {view.params.AI} + "/Gross Unit") ``` You don't need to add the .value part. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [March 4, 2024, 4:20pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/3 "2024-03-04T16:20:57Z")
Soham, a tip: [Wiki - how to post code on this forum](https://forum.inductiveautomation.com/t/wiki-how-to-post-code-on-this-forum/77831). ---
**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:** [March 4, 2024, 4:38pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/4 "2024-03-04T16:38:13Z")
This will work, but note that for performance you should really use two custom properties with indirect tag bindings, and do the sum in a single expression referencing those two custom properties. The `tag()` function can't be optimized the same way indirect tag bindings can, so it's a performance pitfall. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [March 4, 2024, 4:54pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/5 "2024-03-04T16:54:01Z")
> [@paul-griffith](#): > > performance ~~pitfall~~ _ **disaster** _. Fixed that for you. Really, if you are using the `tag()` expression function in a User Interface binding, you are screwing up. Full stop. The **only** appropriate place to use the `tag()` expression function is to perform indirection within an **expression tag**. Nowhere else. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [March 4, 2024, 4:57pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/6 "2024-03-04T16:57:40Z")
> [@pturmel](#): > > Really, if you are using the `tag()` expression function in a User Interface binding, you are screwing up. Phil, you can suggest this be included in the manual. Drop them a line: [docs@inductiveautomation.com](mailto:docs@inductiveautomation.com)! ---
**Author:** ![Soham\_Ambekar](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@Soham\_Ambekar](https://forum.inductiveautomation.com/u/Soham_Ambekar)\ **Post date:** [March 4, 2024, 5:37pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/7 "2024-03-04T17:37:23Z")
> [@leonardo.godoi](#): > > ```auto > tag("[SBR]Seed Receiving/"+ {view.params.AI} + "/Gross Value") + > tag("[SBR]Seed Receiving/"+ {view.params.AI} + "/Gross Unit") > > ``` It worked. Thanks alot ---
**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\ **Post date:** [March 4, 2024, 5:45pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/8 "2024-03-04T17:45:26Z")
> [@Soham\_Ambekar](#): > > It worked. Thanks alot Read > [@paul-griffith](#): > > This will work, but note that for performance you should really use two custom properties with indirect tag bindings, and do the sum in a single expression referencing those two custom properties. The `tag()` function can't be optimized the same way indirect tag bindings can, so it's a performance pitfall and > [@pturmel](#): > > The **only** appropriate place to use the `tag()` expression function is to perform indirection within an **expression tag**. Nowhere else. You start using that in multiple places you will eventually have to pay the piper. ---
**Author:** ![Soham\_Ambekar](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@Soham\_Ambekar](https://forum.inductiveautomation.com/u/Soham_Ambekar)\ **Post date:** [March 4, 2024, 6:11pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/9 "2024-03-04T18:11:20Z")
can you explain it? I didn't get you ---
**Author:** ![leonardo.godoi](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/leonardo.godoi/32/27178_2.png) [@leonardo.godoi](https://forum.inductiveautomation.com/u/leonardo.godoi)\ **Post date:** [March 4, 2024, 7:16pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/10 "2024-03-04T19:16:57Z")
The Tag() expression function i've used can't be optimized as well as an indirect tag binding. Given that, the best way to achieve this will be to instead of using two Tag() functions, we'll create two custom properties on your component, let's call them tagValue and tagUnit and each of them will have an indirect binding and they'll look something like this: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/6/a60cc6c73de3c48a92d31bd7f826356c0bf80f11.png) Then on your props.text property instead of the expression with two Tag() functions, you'll just add the two properties together like this: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/b/ab9bcc9d37a845076771e4a41ab4c3c9de0252c2.png) ```auto {this.custom.tagValue} + {this.custom.tagUnit} ``` ---
**Author:** ![Soham\_Ambekar](https://avatars.discourse-cdn.com/v4/letter/s/b2d939/32.png) [@Soham\_Ambekar](https://forum.inductiveautomation.com/u/Soham_Ambekar)\ **Post date:** [March 4, 2024, 7:31pm UTC](https://forum.inductiveautomation.com/t/indirect-tagging-in-expression/86771/11 "2024-03-04T19:31:59Z")
okay great explanation. Thankyou so much @leonardo.godoi