To_dictionary

To_dictionary can be used to convert an array into multiple objects where each object takes the value of a defined key.

Syntax

json_object to_dictionary(array $input, expr &key, expr &value)

Groups all objects within the $input array by a defined common &key. It converts the input array into a single object which in turn contains an object for each unique &key and applies an expression defined by &value to each of these objects.

Parameters

$input: The array to evaluate.
$key: The items within each array to group by.
$value: The expression to apply to object.

Example

{
  "SalesData": [
    {
      "Region": "Germany",
      "Product": "Apple",
      "Units": "51"
    },
    {
      "Region": "Denmark",
      "Product": "Apple",
      "Units": "99"
    },
    {
      "Region": "Germany",
      "Product": "Orange",
      "Units": "66"
    },
    {
      "Product": "Apple",
      "Units": "51"
    }
  ]
}

{
  SalesDataByRegion: to_dictionary(SalesData, &Region, &@.Product)
}

{
  "SalesDataByRegion": {
    "Germany": [
      "Apple",
      "Orange"
    ],
    "Denmark": [
      "Apple"
    ],
    "_": [
      "Apple"
    ]
  }
}

This example shows to_dictionary being used to create a list of each product sold in a region where both the product name and region names exist as key/value pairs within each object. Two of these objects have a region with value Germany, one has a region with value Denmark and one has no region value. The $value expression then uses the current node scope operator to extract ONLY the Product from each object. The result is a list of each product per region.

Notes

Where the defined key does not exist, objects will be grouped together under a default key, “_”.