Delphi DLL

JSON: Nested Array

See more JSON Examples

Here we have a JSON object that contains nested arrays. This example demonstrates how to access the contents of the nested arrays.

{
 "numbers" : [ 
    ["even", 2, 4, 6, 8], 
    ["prime", 2, 3, 5, 7, 11, 13] 
  ] }

Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, JsonArray, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
json: HCkJsonObject;
jsonStr: PWideChar;
outerArray: HCkJsonArray;
numArrays: Integer;
i: Integer;
innerArray: HCkJsonArray;
numInnerItems: Integer;
j: Integer;

begin
success := False;

json := CkJsonObject_Create();

// This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
// The presence of whitespace chars for pretty-printing makes no difference to the Load
// method. 
jsonStr := '{ "numbers" : [ ["even", 2, 4, 6, 8], ["prime", 2, 3, 5, 7, 11, 13] ] }';

success := CkJsonObject_Load(json,jsonStr);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkJsonObject__lastErrorText(json));
    Exit;
  end;

// Get the value of the "numbers" object, which is an array that contains JSON arrays.
outerArray := CkJsonObject_ArrayOf(json,'numbers');
if (CkJsonObject_getLastMethodSuccess(json) = False) then
  begin
    Memo1.Lines.Add('numbers array not found.');
    Exit;
  end;

numArrays := CkJsonArray_getSize(outerArray);

for i := 0 to numArrays - 1 do
  begin

    innerArray := CkJsonArray_ArrayAt(outerArray,i);

    // The first item in the innerArray is a string
    Memo1.Lines.Add(CkJsonArray__stringAt(innerArray,0) + ':');

    numInnerItems := CkJsonArray_getSize(innerArray);

    for j := 1 to numInnerItems - 1 do
      begin

        Memo1.Lines.Add('  ' + IntToStr(CkJsonArray_IntAt(innerArray,j)));

      end;

    CkJsonArray_Dispose(innerArray);
  end;

CkJsonArray_Dispose(outerArray);

CkJsonObject_Dispose(json);

end;