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distinctBy

distinctBy(Array<T>, (item: T, index: Number) -> Any): Array<T>

Returns unique values from a list (array) that might have duplicates.

Parameters

Name Description

items

The list (Array type).

criteria

The item and/or index used to return.

Example

This example removes duplicates of "Kurt Cagle" from an input array.

Source

%dw 2.0
output application/json
var record =  {
  "title": "XQuery Kick Start",
  "author": [
    "James McGovern",
    "Per Bothner",
    "Kurt Cagle",
    "James Linn",
    "Kurt Cagle",
    "Kurt Cagle",
    "Kurt Cagle",
    "Vaidyanathan Nagarajan"
  ],
  "year":"2000"
}
---
{
    "book" : {
      "title" : record.title,
      "year" : record.year,
      "authors" : record.author distinctBy $
    }
}

Output

{
  "book": {
    "title": "XQuery Kick Start",
    "year": "2000",
    "authors": [
      "James McGovern",
      "Per Bothner",
      "Kurt Cagle",
      "James Linn",
      "Vaidyanathan Nagarajan"
    ]
  }
}

distinctBy(Null, (item: Nothing, index: Nothing) -> Any): Null

Helper function that allows distinctBy to work with null values.

distinctBy({ (K)?: V }, (value: V, key: K) -> Any): Object

Removes duplicate key-value pairs from an Object.

Parameters

Name Description

object

The object from which to remove the key-value pairs.

criteria

The key and/or value used to identify the key-value pairs to remove.

Example

This example removes duplicates (<author>James McGovern</author>) from <book/>.

Source

%dw 2.0
output application/xml
---
{
   book : {
     title : payload.book.title,
     authors: payload.book.&author distinctBy $
   }
}

Input

<book>
  <title> "XQuery Kick Start"</title>
  <author>James Linn</author>
  <author>Per Bothner</author>
  <author>James McGovern</author>
  <author>James McGovern</author>
  <author>James McGovern</author>
</book>

Output

<book>
  <title> "XQuery Kick Start"</title>
  <authors>
      <author>James Linn</author>
      <author>Per Bothner</author>
      <author>James McGovern</author>
  </authors>
</book>

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