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keySet

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.

keySet(T): ?

Returns the list of key names from an object.

Parameters

Name Description

object

The object to evaluate.

Example

This example returns the keys from the input object.

Source

%dw 2.0
import * from dw::core::Objects
output application/json
---
{ "keySet" : keySet({ "a" : true, "b" : 1}) }

Output

{ "keySet" : ["a","b"] }

Example

This example illustrates a difference between keySet and nameSet. Notice that keySet retains the attributes (name and lastName) and namespaces (xmlns) from the XML input, while nameSet returns null for them because it does not retain them.

Source

%dw 2.0
import * from dw::core::Objects
var myVar = read('<users xmlns="http://test.com">
                     <user name="Mariano" lastName="Achaval"/>
                     <user name="Stacey" lastName="Duke"/>
                  </users>', 'application/xml')
output application/json
---
{ keySetExample: flatten([keySet(myVar.users) map $.#,
                          keySet(myVar.users) map $.@])
}
++
{ nameSet: flatten([nameSet(myVar.users) map $.#,
                    nameSet(myVar.users) map $.@])
}

Output

{
  "keySet": [
    "http://test.com",
    "http://test.com",
    {
      "name": "Mariano",
      "lastName": "Achaval"
    },
    {
      "name": "Stacey",
      "lastName": "Duke"
    }
  ],
  "nameSet": [
    null,
    null,
    null,
    null
  ]
}