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filter

DataWeave 2.1 is compatible with Mule 4.1. Standard Support for Mule 4.1 ended on November 2, 2020, and this version of Mule will reach its End of Life on November 2, 2022, when Extended Support ends.

Deployments of new applications to CloudHub that use this version of Mule are no longer allowed. Only in-place updates to applications are permitted.

MuleSoft recommends that you upgrade to the latest version of Mule 4 that is in Standard Support so that your applications run with the latest fixes and security enhancements.

filter(Array<T>, (item: T, index: Number) -> Boolean): Array<T>

Filters a list (array) by applying an expression that returns only the matching items from the list.

The expression must return true or false. If the expression returns true for an element, the element remains in the list. If it returns false for an element, the element gets filtered out of the results.

Parameters

Name Description

items

The list (array) to filter.

criteria

Function that receives an item and index and returns true if the element should remain.

Example

This example returns an array of all elements greater than 2.

Source

[9,2,3,4,5] filter (myitem, myindex) -> (myitem > 2)

Output

[9,3,4,5]

Example

This example returns an array of all elements found at an index greater than 2.

Source

[9,2,3,4,5] filter ((myitem, myindex) -> (myindex > 2))

Output

[4,5]

Example

This example returns an array of all elements found at an index ($$) greater than 1 where the value of the element is less than 5.

Source

%dw 2.0
output application/json
---
[9, 2, 3, 4, 5] filter (($$ > 1) and ($ < 5))

Output

[3,4]

filter(Null, (item: Nothing, index: Nothing) -> Boolean): Null

Helper function that allows filter to work with null values.