How can I efficiently filter a two-dimensional array in PHP by a specific value?

Efficiently Filtering a Two-Dimensional Array by Value in PHP

In PHP programming, efficiently filtering a two-dimensional array by a specific value can be achieved using the versatile array_filter function in combination with a callback.

Simple Filtering by a Single Value

To filter an array by a specific value in a key, we can use the following syntax:

$new = array_filter($arr, function ($var) {
    return ($var['name'] == 'CarEnquiry');
});

Here, $arr is the input array, and the callback function checks if the name key in each sub-array matches the target value. The resulting $new array contains only the sub-arrays where name equals 'CarEnquiry'.

Interchangeable Filtering for Multiple Values

If the target value may vary, we can enhance the callback function to handle interchangeable filtering:

$filterBy = 'CarEnquiry'; // or Finance etc.

$new = array_filter($arr, function ($var) use ($filterBy) {
    return ($var['name'] == $filterBy);
});

The use keyword in the callback function allows us to access the $filterBy variable, which can be modified to specify different target values, allowing dynamic filtering.

Example Usage

Consider the following array as an example:

$arr = [
    [
        'interval' => '2014-10-26',
        'leads' => 0,
        'name' => 'CarEnquiry',
        'status' => 'NEW',
        'appointment' => 0
    ],
    [
        'interval' => '2014-10-26',
        'leads' => 0,
        'name' => 'CarEnquiry',
        'status' => 'CALL1',
        'appointment' => 0
    ],
    [
        'interval' => '2014-10-26',
        'leads' => 0,
        'name' => 'Finance',
        'status' => 'CALL2',
        'appointment' => 0
    ],
    [
        'interval' => '2014-10-26',
        'leads' => 0,
        'name' => 'Partex',
        'status' => 'CALL3',
        'appointment' => 0
    ]
];

Filtering $arr to include only entries where name equals 'CarEnquiry' results in:

$filtered = array_filter($arr, function ($var) {
    return ($var['name'] == 'CarEnquiry');
});

The resulting $filtered array will contain:

Array
(
    [0] => Array
        (
            [interval] => 2014-10-26
            [leads] => 0
            [name] => CarEnquiry
            [status] => NEW
            [appointment] => 0
        )

    [1] => Array
        (
            [interval] => 2014-10-26
            [leads] => 0
            [name] => CarEnquiry
            [status] => CALL1
            [appointment] => 0
        )

    )

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