Power Automate (WDL) function
join — Power Automate (WDL) function reference
Join an array into a string.
Syntax
wdl
join(collection, delimiter)
Examples
wdl
join(variables('tags'), ', ')→ "x, y, z"
wdl
join(variables('emailList'), ';')→ "a@x.com;b@x.com;c@x.com"
wdl
concat('Approvers: ', join(body('Get_items')?['value'], ' and '))→ "Approvers: Alex and Priya"
Common mistakes & gotchas
- join() requires an array of strings — an array containing numbers or objects throws a template error; project to strings upstream (e.g. with a Select action) first.
- There is no built-in "different last separator" option for an Oxford-style list — build that manually with first()/last()/take()/skip() if needed.
Related Workflow Definition Language functions
From Arrays & collections