MakeJSON
New to Analytica 5.0
This function requires the Analytica Enterprise edition or higher (i.e., higher editions are Analytica Optimizer, ADE or CubePlan]).
MakeJSON( x, indexOrder, objects, flags )
Returns text in JavaScript Object Notation (JSON)] format representing the data in «x». When there are multidimensional arrays, you can control the nesting order in the JSON text by specifying the indexes in the «indexOrder» parameter. When some indexes encode the member names of a JavaScript object, you should list those indexes in «objects». The optional «flags» parameter accepts an integer that encodes a bit-field of options, with these options.
- 1 = Don't infer that 1-D arrays with textual indexes are objects.
- 2 = reserved. Must be 0.
- 4 = Issue an error if there is an object inconsistency.
- 8 = Top-level element in the result can be a non-object.
- 16 = Allow ragged arrays.
JSON Objects vs. Arrays
Consider the following array in Variable Biblio1984
One way to encode this is JSON is an a JSON object.
MakeJSON( Biblio1984, objects: Biblio )→'{"title": "1984", "author": "George Orwell", "year": 1949, "pages": 336, "paperback": 1}'
A second way to encode the same array data is an a JSON array.
MakeJSON( Biblio1984, indexOrder:Biblio, flags:8 )→'["1984", "George Orwell", 1949, 336, 1]'
Because the top-most item is JSON text is supposed to a JSON object, this second example isn't strictly valid (the «flags»=8 option was required for this reason). But for information anywhere other than the outermost dimension of «x», the fact remains that the data in an Analytica array can be placed in either form -- JSON-object or JSON-array.
For any index in your data, you can make it explicit by listing the index in the «objects» parameter if you want it to produce a JSON object, or in the «indexOrder» parameter if you want it to produce a JSON-array for that index. When you don't set the «flags»=8 bit, one index will be selected as an object index, even if they are all listed in «indexOrder», just because JSON text is supposed to have the root be an object.
When «x» contains an index that you have not explicitly listed, it will infer that it should be an object when the «flags»=1 is not set, the array is 1-D, and the index has textual member names. Otherwise it will output it as an array without the index labels.
Index order
When an Analytica array has more that one-dimension, you should list the indexes in «indexOrder», with the index that should vary most slowly listed first. For example:
Index I :=1..4Index J :=1..3Index K :=['k1', 'k2']Variable z1 :=10 * J + @KVariable z2 :=100*I + @KIndex Struct :=['z1', 'z2']Variable data1 ;= Table(Struct)( \z1, \z2 )
You should think of data1 as being like an instantiation of a class named Struct, which has two members z1 and z2. The z1 member of data1 has a 2-D array indexed by J, K, and the z2 member has a 2-D array indexed by K, K.
If we don't specify the index order, you can't reliably predict which nesting of the array data will result.
MakeJSON( data1 ) → { "z1": [[11, 12], [21, 22], [31, 32]], "z2": [[101, 201, 301, 401], [102, 202, 302, 402]] }
Note: MakeJSON does not insert newlines or indents. The result was formatted above manually.
It may be that the application code receiving this expects the data to be in K-major order. In the above, z2 was as desired, but z1 was transposed. To ensure this, you need to specify the «indexOrder».
MakeJSON( data1, indexOrder: K, J, I ) → { "z1": [[11, 21, 31], [12, 22, 32]], "z2": [[101, 201, 301, 401], [102, 202, 302, 402]] }
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