如何使用JSONata按指定键对JSON数组中的对象进行分组

To group your array of car objects by the car key, you can use JSONata's built-in $groupBy function—it’s tailored exactly for this kind of grouping task.

Input Data #

[
  { "car": "audi", "color": "blue", "reg": 133434 },
  { "car": "benz", "color": "red", "reg": 134444 },
  { "car": "audi", "color": "red", "reg": 134884 }
]

JSONata Expression #

$groupBy($, "car")

Explanation #

• $ refers to the entire input array (the root context for this query).
• "car" is the property selector—JSONata uses the value of this property from each object as the key in the final grouped object.
• The $groupBy function handles all the heavy lifting: it iterates through the array, groups objects with matching car values, and collects each group into an array under the corresponding key.

Result #

{
  "audi": [
    { "car": "audi", "color": "blue", "reg": 133434 },
    { "car": "audi", "color": "red", "reg": 134884 }
  ],
  "benz": [
    { "car": "benz", "color": "red", "reg": 134444 }
  ]
}

If you ever need to group by a computed key instead of a direct property (like grouping by uppercase car names), you can replace the "car" string with an expression (e.g., $uppercase(car)), but for your specific use case, the simple property selector works perfectly.

内容的提问来源于stack exchange，提问作者ARUN KUMAR