Accessing nested values in a table

Processing Coding Questions
13

Yep. But you don’t have to store objects for each row with a row number name. That is needlessly complex. JSON already has an ordered element: array. So you can just do an array of arrays like this for 2D (normal spreadsheet):

[
  [
      50,
      10,
      5,
      50
  ],
  [
      51,
      9,
      6.5,
      58.5
  ]
]

…and for 3D, just do an array of arrays of arrays. Here is your data:

[
  [
    [
      40.65,
      20.3,
      120.92,
      86.12,
      99.33
    ],
    [
      10.35,
      90.1,
      10.52,
      1.12,
      59.3
    ],
    [
      10.65,
      62.1,
      12.12,
      96.23,
      19.3
    ]
  ],
  [
    [
      96.37,
      67.13,
      312.62,
      87.11,
      87.18
    ],
    [
      90.94,
      41.04,
      63.01,
      9.1,
      30.3
    ],
    [
      11.98,
      99.01,
      41.3,
      16.04,
      10.4
    ]
  ],
  [
    [
      11.88,
      12.98,
      182.22,
      13.84,
      81.09
    ],
    [
      50.35,
      10.1,
      10.52,
      8.12,
      91.3
    ],
    [
      88.51,
      21.66,
      81.13,
      36.13,
      97.3
    ]
  ]
]

…or, minified:

[[[40.65,20.3,120.92,86.12,99.33],[10.35,90.1,10.52,1.12,59.3],[10.65,62.1,12.12,96.23,19.3]],[[96.37,67.13,312.62,87.11,87.18],[90.94,41.04,63.01,9.1,30.3],[11.98,99.01,41.3,16.04,10.4]],[[11.88,12.98,182.22,13.84,81.09],[50.35,10.1,10.52,8.12,91.3],[88.51,21.66,81.13,36.13,97.3]]]

You can access it with JSONArray.

String jsondata = "[[[40.65,20.3,120.92,86.12,99.33],[10.35,90.1,10.52,1.12,59.3],[10.65,62.1,12.12,96.23,19.3]],[[96.37,67.13,312.62,87.11,87.18],[90.94,41.04,63.01,9.1,30.3],[11.98,99.01,41.3,16.04,10.4]],[[11.88,12.98,182.22,13.84,81.09],[50.35,10.1,10.52,8.12,91.3],[88.51,21.66,81.13,36.13,97.3]]]";

JSONArray ja = parseJSONArray(jsondata);

int row = 2;
int col = 0;
int val = 1;

float val = ja.getJSONArray(row).getJSONArray(col).getFloat(val);
println(val);  // 182.22

…and you can wrap that code up in a function to make it shorter:

float ja3Dfloat(JSONArray ja, int row, int col, int item){
  return ja.getJSONArray(row).getJSONArray(col).getFloat(val)
}
//...
ja3Dfloat(ja, 2, 0, 1);  // 182.22
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