# Reaching a document value in a Tag using expression **URL:** \ **Category:** Ignition\ **Created:** [April 20, 2021, 1:46pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810 "2021-04-20T13:46:23Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![kghali](https://avatars.discourse-cdn.com/v4/letter/k/da6949/32.png) [@kghali](https://forum.inductiveautomation.com/u/kghali)\ **Post date:** [April 20, 2021, 1:46pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/1 "2021-04-20T13:46:24Z")
I have a UDT, inside it there is root R and inside it there are memory tags. one of the memory tags has a value {document}. Inside {document} there is object which has another object that has some values that I want to access with expression: [~]my folder/R/mytag → Value → 2nd object → first parameter ---
**Author:** ![kcollins](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kcollins/32/19646_2.png) [@kcollins](https://forum.inductiveautomation.com/u/kcollins)\ **Post date:** [April 20, 2021, 2:05pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/2 "2021-04-20T14:05:58Z")
Does this help at all? ![2021-04-20 at 9.05 AM](https://us1.discourse-cdn.com/inductiveautomation/original/3X/3/c/3cdd687a7e596ba26eb97304cd97cef64ce572bf.png) EDIT: I see now you’re looking for an expression solution, so that might not be exactly what you’re looking for, but it might help get you there… ---
**Author:** ![kghali](https://avatars.discourse-cdn.com/v4/letter/k/da6949/32.png) [@kghali](https://forum.inductiveautomation.com/u/kghali)\ **Post date:** [April 20, 2021, 2:18pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/3 "2021-04-20T14:18:10Z")
It helped a lot! Thank you! ---
**Author:** ![rodimir\_vilale](https://avatars.discourse-cdn.com/v4/letter/r/dec6dc/32.png) [@rodimir\_vilale](https://forum.inductiveautomation.com/u/rodimir_vilale)\ **Post date:** [September 24, 2025, 11:23pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/4 "2025-09-24T23:23:50Z")
Hi, I have a somewhat related issue. This one helps, but what if the “bar” in your example is a number? How do I access the value? ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/0/6002e5da887a3880b8b6797cc14cd74dd76eacb2.png) ---
**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:** [September 24, 2025, 11:40pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/5 "2025-09-24T23:40:19Z")
Keys that start with a digit are not permitted in JSON, and therefore not permitted in document tags nor in Perspective. (Though not strictly enforced.) Just don't have such keys. ---
**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:** [September 24, 2025, 11:47pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/6 "2025-09-24T23:47:47Z")
Since the property editor isn't visibly yelling at you, it's likely that your key is actually a string-containing-digits, which you would access using the same subscript/square bracket syntax Kevin posted above. But if it isn't, and also because it's just a confusing idea with poor support in general - as Phil said, don't use numbers as keys. If you need positional referencing...use an array, not an object. ---
**Author:** ![rodimir\_vilale](https://avatars.discourse-cdn.com/v4/letter/r/dec6dc/32.png) [@rodimir\_vilale](https://forum.inductiveautomation.com/u/rodimir_vilale)\ **Post date:** [September 25, 2025, 4:15pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/7 "2025-09-25T16:15:52Z")
Thank you! This helps. I will stop pursuing using digit as keys! ---
**Author:** ![rodimir\_vilale](https://avatars.discourse-cdn.com/v4/letter/r/dec6dc/32.png) [@rodimir\_vilale](https://forum.inductiveautomation.com/u/rodimir_vilale)\ **Post date:** [September 25, 2025, 4:17pm UTC](https://forum.inductiveautomation.com/t/reaching-a-document-value-in-a-tag-using-expression/45810/8 "2025-09-25T16:17:14Z")
Yeah, digits does not work at all. Values are blank, but when I tried changing to a string then it gives me the values.