Removing a Tag in XPath

[Anxiety123]

I want to remove the 'noMods' tag from the nailgun without overwriting the 'Tags' property entirely.

 

The only way I know how to do it is this:

<set xpath="/items/item[@name='meleeToolRepairT3Nailgun']/propery[@name='Tags']/@value">tool,nailgun,sideAttachments,repairTool,attStrength,perkMiner69r,canHaveCosmetic</set>

 

The problem is that would overwrite any tag changes from other mods.  I know we have a 'contains' function to find substring matches, and a quick Google search tells me that XPath has other string functions (substring, substring-before, substring-after, concat, replace).  I don't know how to use anything but 'contains'.  Are they even implemented for 7 Days?