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Filter a list of items based on a property value and optional predicate.<\/p>\n

This filter provides powerful filtering capabilities for lists of maps, proplists, or resources\nby checking property values against predicates.<\/p>\n

Basic Usage<\/h2>\n

Filter items where a property is defined (not undefined<\/code>):<\/p>\n

{{ items | filter_by:"price" }}\n<\/code><\/pre>\n
Returns only items that have a price property defined.<\/p>\n
Using Predicates<\/h2>\n
Filter with a boolean predicate filter:<\/p>\n
{{ items | filter_by:"active":"is_defined" }}\n<\/code><\/pre>\n
This applies the is_defined<\/code> filter to each item's active property. It is possible\nto use all boolean filters.<\/p>\n
Built-in Comparison Operators<\/h2>\n
  • eq<\/code> - equal to<\/li>
  • ne<\/code> - not equal to<\/li>
  • lt<\/code> - less than<\/li>
  • le<\/code> - less than or equal to<\/li>
  • gt<\/code> - greater than<\/li>
  • ge<\/code> - greater than or equal to<\/li>
  • between<\/code> - between two values (inclusive)<\/li>
  • in<\/code> - value is in a list<\/li>
  • not_in<\/code> - value is not in a list<\/li><\/ul>\n
    Examples:<\/p>\n
    {{ products | filter_by:"price":"gt":100 }}\n<\/code><\/pre>\n
    Returns products with price greater than 100<\/code>.<\/p>\n
    {{ items | filter_by:"status":"in":["active", "pending"] }}\n<\/code><\/pre>\n
    Returns items where status is either "active" or "pending".<\/p>\n
    {{ orders | filter_by:"amount":"between":[50, 200] }}\n<\/code><\/pre>\n
    Returns orders with amount between 50 and 200 (inclusive).<\/p>\n
    Filtering Resources<\/h2>\n
    Works seamlessly with Zotonic resources:<\/p>\n
    {{ m.search[{query cat="product"}] | filter_by:"is_published":"eq":true }}\n<\/code><\/pre>\n
    If the input is undefined, the filter returns undefined.<\/p>","slug":"filter_by","is_protected":false,"visible_for":0,"tz":"UTC","language":["en"],"doc_source_hash":"37cb718bdb2aa323d8bcb48e0c6a12a7ceeaea94ff716a353c26b9587d2cae00","is_featured":false,"content_group_id":{"id":2551,"is_a":["meta","content_group"],"name":"content_group_imported_docs","title":"Imported documentation","uri":"https:\/\/zotonic.com\/id\/content_group_imported_docs"},"category_id":{"id":325,"is_a":["meta","category"],"name":"template_filter","title":"Filters","uri":"https:\/\/test.zotonic.com\/id\/325"},"doc_source_path":"apps\/zotonic_mod_base\/src\/filters\/filter_filter_by.erl","publication_start":"2026-02-27T16:43:30Z","github_url":"https:\/\/github.com\/zotonic\/zotonic\/blob\/master\/apps\/zotonic_mod_base\/src\/filters\/filter_filter_by.erl","pivot_location_lng":null,"doc_source_kind":"filter","name":"doc_template_filter_filter_filter_by","is_unfindable":false,"is_published":true,"pivot_geocode":null,"created":"2026-02-27T16:43:30Z","uri":null,"doc_status":"current","is_dependent":false,"erlang_app":"zotonic_mod_base","publication_end":"9999-06-01T00:00:00Z","modifier_id":{"id":1,"is_a":["person"],"name":"administrator","title":"Site Administrator","uri":"https:\/\/zotonic.com\/id\/1"},"privacy":0,"doc_source_commit":"66cb145eae7002b184e7d8c4c7bba5e53e8248e5\n","erlang_module":"filter_filter_by","creator_id":{"id":1,"is_a":["person"],"name":"administrator","title":"Site Administrator","uri":"https:\/\/zotonic.com\/id\/1"},"modified":"2026-10-02T12:40:31Z","title_slug":"filter_by"},"uri":"https:\/\/zotonic.com\/id\/2493","uri_template":"https:\/\/zotonic.com\/id\/:id","websub":{"hub":"https:\/\/zotonic.com\/.zotonic\/websub","topic":"https:\/\/zotonic.com\/.zotonic\/websub\/topic\/2493"}},"status":"ok"}