Collection template functions

These template functions help you work with collections of data: lists, sets, dictionaries, and JSON. Use them to combine, filter, sort, and reshape data from your entities, API responses, and incoming messages.

Home Assistant extends the Jinja2 template engine with many custom functions, filters, and tests. Each function on this page has its own page with detailed descriptions, parameters, and practical examples.

New to templates? Start with the templating documentation to learn the basics.

• Get object ibute attr Reads an attribute from an object when the attribute name comes from a variable.
• Split list into es batch Splits a list into smaller batches of a specified size.
• Merge dictionaries combine Merges multiple dictionaries into one.
• Sort a dictionary dictsort Sorts a dictionary by its keys or values, returning a list of key/value pairs.
• Set difference Returns items in the first list but not in the second (set difference).
• Get item first Returns the first item of a list or the first character of a string.
• Flatten nested lists flatten Flattens nested lists into a single flat list.
• Parse JSON string from_json Parses a JSON string into a Python object.
• Group items by attribute groupby Groups a list of items by a common attribute, producing a list of (grouper, list) pairs.
• Set ion intersect Returns items common to both lists (set intersection).
• Get dictionary key/value pairs items Returns the key/value pairs from a dictionary as a list of tuples.
• Get item last Returns the last item of a list or the last character of a string.
• Get of a collection length Returns the number of items in a list, characters in a string, or keys in a dictionary. Also available as count.
• Transform list items map Applies a filter to each item or extracts an attribute from each item in a list.
• Merge action responses merge_response Merges action response dictionaries into a flat list.
• Remove items by test reject Filters a list, removing items that pass a given test. The opposite of select.
• Remove items by attribute test rejectattr Filters a list, removing items where a specified attribute passes a test. The opposite of selectattr.
• Reverse a list or string reverse Reverses the order of items in a list or characters in a string.
• Filter items by test select Filters a list, keeping only items that pass a given test.
• Filter items by attribute test selectattr Filters a list, keeping only items where a specified attribute passes a test.
• Convert to set Converts an iterable to a set, removing duplicate values.
• Randomly a list shuffle Randomly shuffles the items in a list.
• Slice a list into sub-lists slice Slices a list into a specified number of sub-lists of roughly equal size.
• Sort a list sort Sorts the items in a list, with optional attribute-based and reverse sorting.
• Sum values in a list sum Sums all values in a list, with optional attribute extraction and start value.
• Set symmetric difference symmetric_difference Returns items in either list but not in both.
• Serialize to JSON to_json Serializes a value to a JSON string.
• Convert to tuple Converts an iterable to a tuple.
• Set union Returns all unique items from both lists (set union).
• Remove duplicate values unique Removes duplicate values from a list, keeping only unique items.