Power Automate: XPath vs Apply to Each

Key insights

• XPath trick: Replace Apply to each by converting a JSON array to XML with xml() and querying it with xpath().
  This avoids looping every item when you only need targeted values or summaries.
• Benefits: You get faster execution on large arrays, fewer actions in the flow, and a simpler design that reduces complexity and action limits.
  Use this when speed and clarity matter more than per-item processing.
• Common operations: Use sum() for totals, first() or [0] to pick a single item, and XPath predicates to filter or group values.
  These let you compute totals, averages, and filtered results without loops.
• Common use cases: Works well with HTTP APIs and SharePoint Get Items, plus lookups, joins, and extracting nested text from OCR or AI outputs.
  Apply it when data already arrives as arrays you need to query or aggregate.
• How it works: Wrap the array in a root node, convert JSON to XML using xml(), run an xpath() expression to select or aggregate, then convert results back if needed.
  This single expression can replace many loop actions.
• Caveats & best practices: Let the backend do aggregation when possible, use Select to shape data first, and prefer loops when each item needs complex logic.
  Test XPath on your data and keep expressions readable to avoid maintenance issues.

Keywords

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