How to build a multi-dimensional array with a recursive function and passing by reference

Question

I want to build and return an array in this format:

[
    [
        'prefLabel' => 'foo',
        'subclasses' => [
            [
                'prefLabel' => 'bar',
                'subclasses' => [
                    [
                        'prefLabel' => 'tee',
                        'subclasses' => [
                            [
                                //.. more of the same
                            ]
                        ]
                    ],
                    [
                        // ...
                    ]
                ]
            ],
            [
                'prefLabel' => 'baz',
                'subclasses' => [
                    [
                        // ...
                    ],
                    [
                        // ...
                    ]
                ]
            ],
        ]
    ],
]

The depth is unknown.

I realize this needs a recursive function, but the way I'm doing it always returns a single dimension, albeit with the correct subclasses:

public function search($keyword)
{
    $resp = $this->searchPrefLabels($keyword);

    foreach($resp->prefLabels as $obj) {
        $return[] = [
            'prefLabel' => $obj->prefLabel,
            'subclasses' => $this->getSubclasses($obj->prefLabel)
        ];
    }

    return $return;
}

// the recursive function
protected function getSubclasses($searchTerm, &$tree_string = []) 
{

    $resp = $this->searchSubClass($searchTerm);
    $tree = [];
    foreach($resp->subclasses as $subclass) {
        $tree[] = [
            'prefLabel' => $subclass->prefLabel
        ];
    }
    if(count($tree)) {
        $tree_string = array_merge($tree_string, $tree);
    }

    foreach($tree as $key => $val) {
        $val['subclasses'] = $this->getSubclasses($val['prefLabel'], $tree_string); 
    }

    return $tree_string;
}

The above returns something similar to the following:

[
    [
        'prefLabel' => 'foo',
        'subclasses' => [
            [
                'prefLabel' => 'bar',
            ],
            [
                'prefLabel' => 'baz',
            ],
            [
                'prefLabel' => 'tee',
            ],
            // ...
    ],
]

I want it to return in the nested format shown above.

@splash58 That did not change the returned format

Angad Dubey
– Angad Dubey

2018-02-21 20:44:08 +00:00
Commented Feb 21, 2018 at 20:44 — Angad Dubey
– Angad Dubey, Commented Feb 21, 2018 at 20:44

CodeBoy · Accepted Answer · 2018-02-21 21:56:37Z

1

I think you only need one function for this recursion (since top level looks like all sub levels):

public function getPreLabelsAndSubClasses($keyword) {
    $result = [];
    $labels = $this->searchPrefLabels($keyword);
    foreach ($labels as $label) {
        $result[] = [
            'prefLabel' => $label,
            'subclasses' => $this->getPreLabelsAndSubClasses($label),
        ];
    }
    return $result;
}

answered Feb 21, 2018 at 21:56

CodeBoy

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1 Comment

Angad Dubey Over a year ago

There is a separate call to get subclasses though: $resp = $this->searchSubClass($searchTerm); How do I incorporate this in the solution you suggested?

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