JSONLab

https://neurojson.org/jsonlab
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JSONLab is an open-source JSON, Binary JData, UBJSON, and MessagePack encoder and decoder for MATLAB...
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### Install via Fedora Package Manager

Source: https://neurojson.org/jsonlab

Install the JSONLab and ZMat packages using the dnf package manager.

```bash
sudo dnf install octave-jsonlab
sudo dnf install octave-zmat
```

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### Install via Debian/Ubuntu Package Manager

Source: https://neurojson.org/jsonlab

Install the JSONLab package using the apt-get package manager.

```bash
sudo apt-get install octave-jsonlab
```

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### Binary Format Processing

Source: https://neurojson.org/jsonlab

Examples for working with Binary JData, MessagePack, and UBJSON formats.

```matlab
% Binary JData with savebj/loadbj (smaller, faster)
data = struct('string', 'value', 'array', single([1 2 3]));
savebj('', data, 'filename', 'data.bjd');
data = loadbj('data.bjd');

% MessagePack with savemsgpack/loadmsgpack
savemsgpack('', data, 'data.msgpk');
data = loadmsgpack('data.msgpk');

% UBJSON with saveubjson/loadubjson
saveubjson('', data, 'data.ubj');
data = loadubjson('data.ubj');
```

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### Clone JSONLab from GitHub

Source: https://neurojson.org/jsonlab

Download the source code repository directly from GitHub.

```bash
git clone https://github.com/NeuroJSON/jsonlab.git
```

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### Basic JSONLab Usage

Source: https://neurojson.org/jsonlab

Demonstrates saving and loading data using standard JSON and the unified savejd/loadjd interface.

```matlab
% Save MATLAB data to JSON with savejson
data = struct('name', 'JSONLab', 'version', 2.9, 'array', [1,2,3]);
savejson('', data, 'filename', 'output.json');

% Load JSON file with loadjson
data = loadjson('output.json');

% Unified interface: savejd/loadjd auto-detect format
savejd('', data, 'output.json');
data = loadjd('output.json');
```

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### Manual MATLAB Path Configuration

Source: https://neurojson.org/jsonlab

Add the JSONLab directory to the MATLAB search path and refresh the path cache.

```matlab
addpath('/path/to/jsonlab');
rehash;
```

--------------------------------

### Data Linking and Caching

Source: https://neurojson.org/jsonlab

Download remote datasets and manage local file caching using jdlink and jsoncache.

```matlab
% jdlink: dynamically download from REST APIs
% Load dataset from NeuroJSON.io with loadjson
ds = loadjson('https://neurojson.io:7777/openneuro/ds000001');

% Find linked files with jsonpath
links = jsonpath(ds, '$..anat.._DataLink_');

% Download files matching regex pattern with jdlink
files = jdlink(links, 'regex', 'sub-01_.*\.nii');

% Check cache location with jsoncache
[cache_path, fname] = jsoncache(...
    'https://neurojson.io:7777/openneuro/ds000001');

% Files cached in ~/.neurojson/ for fast reuse
```

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### JData Format Encoding and Decoding

Source: https://neurojson.org/jsonlab

Shows how to handle complex MATLAB data types, sparse arrays, and compression using JData.

```matlab
% JData format: encode complex MATLAB data with jdataencode
raw = struct('complex', 2+4i, 'sparse', sparse(eye(5)));
encoded = jdataencode(raw);
savejson('', encoded);

% Decode JData back to MATLAB with jdatadecode
decoded = jdatadecode(encoded);

% 3D arrays with type preservation
data3d = reshape(1:24, 2, 3, 4);
savejson('', data3d, 'NestArray', 0);

% Compressed arrays in JSON/BJData
savejson('', eye(100), 'Compression', 'zlib', 'CompressArraySize', 1);
```

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### JSONPath Data Querying

Source: https://neurojson.org/jsonlab

Utilize JSONPath expressions to navigate, slice, and filter nested MATLAB structures.

```matlab
% Query data structures with jsonpath
data = struct('book', struct('title', {'Yoda', 'Jinn', 'Kenobi'}, ...
              'author', {'Master', 'Qui-Gon', 'Obi-Wan'}));

% Get nested field
titles = jsonpath(data, '$.book.title')

% Deep scan with .. operator
authors = jsonpath(data, '$..author')

% Array slicing [start:end]
first_two = jsonpath(data, '$.book.title[0:1]')

% Negative indices (last element)
last_item = jsonpath(data, '$.book.title[-1]')
```

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### JDict Attribute Access

Source: https://neurojson.org/jsonlab

Access and modify nested fields and metadata using xarray-like syntax in MATLAB.

```matlab
% jdict: xarray-like attribute access for MATLAB
data = struct('exp', struct('trials', rand(10,5)));
jd = jdict(data);

% Access nested fields with ()
trials = jd.('exp').('trials');

% Use JSONPath syntax
trials = jd.('$.exp.trials');

% Modify values with .v() accessor
jd.('exp').('trials').v(1) = 999;

% Add xarray-like attributes with {}
jd.('exp').('trials'){'dims'} = {'time', 'channels'};
jd.('exp').('trials'){'units'} = 'microvolts';
```
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