# filter\_by Source: https://zotonic.com/docs/2493/filter_by URI: https://zotonic.com/id/2493 Language: en Filter a list of items based on a property value and optional predicate. This filter provides powerful filtering capabilities for lists of maps, proplists, or resources by checking property values against predicates. Basic Usage ----------- Filter items where a property is defined (not `undefined`): ```django {{ items | filter_by:"price" }} ``` Returns only items that have a price property defined. Using Predicates ---------------- Filter with a boolean predicate filter: ```django {{ items | filter_by:"active":"is_defined" }} ``` This applies the `is_defined` filter to each item's active property. It is possible to use all boolean filters. Built-in Comparison Operators ----------------------------- - `eq` - equal to - `ne` - not equal to - `lt` - less than - `le` - less than or equal to - `gt` - greater than - `ge` - greater than or equal to - `between` - between two values (inclusive) - `in` - value is in a list - `not_in` - value is not in a list Examples: ```django {{ products | filter_by:"price":"gt":100 }} ``` Returns products with price greater than `100`. ```django {{ items | filter_by:"status":"in":["active", "pending"] }} ``` Returns items where status is either "active" or "pending". ```django {{ orders | filter_by:"amount":"between":[50, 200] }} ``` Returns orders with amount between 50 and 200 (inclusive). Filtering Resources ------------------- Works seamlessly with Zotonic resources: ```django {{ m.search[{query cat="product"}] | filter_by:"is_published":"eq":true }} ``` If the input is undefined, the filter returns undefined. License: Attribution: Related resources: https://zotonic.com/api/agent/related/2493?language=en ## API access - [API help]() - [OpenAPI specification]() - [This resource as JSON]()