list_join

TABLE OF CONTENTS

• Definition
• Parameters
• Returns
• Examples

Join lists of objects

Definition

array list_join(array[object] $leftArray, array[object] $rightArray, &leftEvaluateBy, &rightEvaluateBy)

Joins the objects of two arrays of objects. &leftEvaluateBy and &rightEvaluateBy are treated as object identifiers; the objects that have matching values of &leftEvaluateBy and &rightEvaluateBy will be joined into a single object with properties left and right, whose values are arrays of all the objects in $leftArray and $rightArray respectively, that have the same value of &leftEvaluateBy and &rightEvaluateBy. The objects also have a property __index, which is the position of the object in the resulting list.

Entries that do not have matching keys, either in $leftArray or $rightArray, are shown in the result with no matching counterpart.

Parameters

array[object] $leftArray

Left array to join.

array[object] $rightArray

Right array to join.

&leftEvaluateBy

Identifier key for the objects in the left array.

&rightEvaluateBy

Identifier key for the objects in the right array.

Returns

array

Array where the objects with matching &EvaluateBy values have been joined together.

Examples

{
   "people": [
     { "name": "Messi", "teamId": 1 },
     { "name": "Iniesta", "teamId": 1 },
     { "name": "Ronaldo", "teamId": 2 },
     { "name": "Rooney", "teamId": 3 }
   ],
   "teams": [
     { "name": "Barcelona", "id": 1 },
     { "name": "Real Madrid", "id": 2 },
     { "name": "Real", "id": 2 },
     { "name": "Liverpool", "id": 10 }
   ]
}

{
  list_join: list_join(people, teams, &teamId, &id)
}

{
  "list_join":
    [
      {
        "left":[{"name": "Messi", "teamId": 1}, {"name": "Iniesta", "teamId": 1}],
        "right":[{"name": "Barcelona", "id": 1}],
        "__index": 0
      },
      {
        "left":[{"name": "Ronaldo", "teamId": 2}],
        "right":[{"name": "Real Madrid", "id": 2}, {"name": "Real", "id": 2}],
        "__index": 1
      },
      {
        "left":[{"name":"Rooney", "teamId": 3}],
        "right":[],
        "__index": 2
      },
      {
        "left":[],"right":[{"name":"Liverpool","id": 10}],
        "__index": 3
      }
    ]
}