IJsonElement.Query

Syntax

Query(Path: String): IJsonArray;

Parameters

Path. JSONPath query to get child elements.

Description

The Query method returns the array of elements obtained by executing a JSONPath query.

Comments

When creating various conditions in a query take into account the specified data type. Implicit type conversion is not supported. Information about JSONPath query syntax is given in description of the jsoncons library, which was used for implementation of Fore kernel to work with JSON structures: https://github.com/danielaparker/jsoncons/blob/master/doc/ref/jsonpath/jsonpath.md.

Example

Executing the example requires the JSON file: d:\Work\Json\data.json. The file has the following approximate structure:

JSON file

{    "product": [
        {
            "name": "Product 1",
            "price": 100
        },
        {
            "name": "Product 2",
            "price": 200
        },
        {
            "name": "Product 3",
            "price": 300
        },
        {
            "name": "Product 4",
            "price": 400
        }
    ]
}

Sub UserProc;
Var
    Doc: IJsonDocument;
    JSONArray: IJsonArray;
Begin
    Doc := New JsonDocument.Create;
    Doc.ReadFromFile("d:\Work\Json\data.json");
    JSONArray := Doc.RootElement.Query("$.product[?(@.price > 50 && @.price < 350)]");
    Debug.WriteLine("Number of selected elements: " + JSONArray.Count.ToString);
End Sub UserProc;

After executing the example, the JSON structure will be read from the file. This structure will be requested to select elements according to the specified condition. The number of selected elements will be displayed in the development environment console.