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filter

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.

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