how can I cause jsondecode to add [ ]

Hi

In order to create a JSON file that is suitable for another application out of Matlab, I arranged all the needed parameters as fieldName of struct array like in the code below. but ,unfortunately, in the output it missing [ ] on the "regions" subfieldNames .

how can I fix it with Matlab.

Many thanks to the helpers.

the code for 1 file as an example

for c=1:1 %numel(X)/2
    jsonformat1.filename=string(J{c,1});
    jsonformat1.size=J{c,2};
    jsonformat1.regions.shape_attributes.name="polygon";
    jsonformat1.regions.shape_attributes.all_points_x=J{c,3};
    jsonformat1.regions.shape_attributes.all_points_y=J{c,4};
    jsonformat1.regions.region_attributes.name="not difined";
    jsonformat1.regions.region_attributes.type="unknown";
    jsonformat1.regions.region_attributes.image_quality.good="true";
    jsonformat1.regions.region_attributes.image_quality.frontal="true";
    jsonformat1.regions.region_attributes.image_quality.good_illumination="true";
    jsonformat1.file_attributes.caption={};
    jsonformat1.file_attributes.public_domain="no";
    jsonformat1.file_attributes.image_url={};
    
end
jsonencode(jsonformat1)

the output from matlab

'{"filename":"case100im16.jpg","size":207942,"region":{"shape_attributes":{"name":"polygon","all_points_x":[425,432,442,452,449,468,465,495],"all_points_y":[370,372,353,354,321,314,305,312,]},"region_attributes":{"name":"not difined","type":"unknown","image_quality":{"good":"true","frontal":"true","good_illumination":"true"}}},"file_attributes":{"caption":[],"public_domain":"no","image_url":[]}}'

the output needed to the other application ( addition of " [ " before "shape_attributes" and " ] "before "file_attributes")

'{"filename":"case100im16.jpg","size":207942,"region":[{"shape_attributes":{"name":"polygon","all_points_x":[425,432,442,452,449,468,465,495],"all_points_y":[370,372,353,354,321,314,305,312,]},"region_attributes":{"name":"not difined","type":"unknown","image_quality":{"good":"true","frontal":"true","good_illumination":"true"}}}],"file_attributes":{"caption":[],"public_domain":"no","image_url":[]}}'

[Geoff Hayes]

@uriel shitrit - the [] indicates an array so it isn't clear to me why these square brackets would be required for the "region" field..unless you are allowing for multiple shape_attributes?

[uriel shitrit]

I really don't know why it was needed I just saw that when I manually add it to the file the other application succeeds to load and read the file

Answer 1

[Prince Kumar]

Hi,

You can create another json which you want to put in [].

You can refer the following implementation

jsonformat1.filename= "file_name";
jsonformat1.size=12;

subjson.shape_attributes = "polygon";
subjson.region_attributes.name="not difined";
subjson.region_attributes.type="unknown";

jsonformat1.region = {subjson};
jsonformat1.file_attributes.public_domain="no";

jsonencode(jsonformat1)

In the above example subjson has the data that you want to put in [].

I hope you find this information useful.