Set variable based on another

I am looking to set a variable without user interaction based on another variable.

I have a variable where the user chooses the device. “device - sn”.

But i would like to automatically set another var for the SN that other linked dashboards will use that is only going to be the sn.

I was thinking of defining a var thats a regex of an existing one, but could not see how to do that.

Is there a way i can do that?

can you show your code? i dont understand it

For example i have a var that is used for a panel to repeat, and that further pushes to a detail panel via a link with the var being passed. That var is a query to the influxdb to populate it:

show tag values from dellsc_san_disks with key="hostname"

With results like: array1 - 111111 array2 - 22222 array3 - 33333. Thats a format of “Name - SerialNumber”

On the detail dashboard i have to use a different datasource (mssql) that requires only the SN, rather than the name being passed. So i would like to have a var named SN on that dashboard that could be just the SN part of the name and would be defined on dashboard load. Thats why i thought if i could use the regex of the var value and set that to a new var named SN the details dashboard would have it available to use with no user input. Other wise i think i am left forcing the user to select the SN on the details dashboard.

can yu make image ? soory to much text

I ended up doing this with a chain variable and using the regex of /\s\S*\s(.*)/gm

why you asked then ?

I asked because i did not know how to do it. But i did continue to research, and wanted to share the solution i had , in case it could help others.

but me and others were researching all the waste time

Could you show me more detail like capture screen?