What are some best practices for grouping and counting data in PHP arrays based on specific criteria, such as dates or names?

When grouping and counting data in PHP arrays based on specific criteria such as dates or names, one effective approach is to use the array_reduce() function along with a custom callback function. This allows you to iterate over the array, group the data based on the specified criteria, and count the occurrences of each group. 

$data = [
    ['name' => 'Alice', 'date' => '2022-01-01'],
    ['name' => 'Bob', 'date' => '2022-01-01'],
    ['name' => 'Alice', 'date' => '2022-01-02'],
    ['name' => 'Alice', 'date' => '2022-01-02'],
];

$groupedData = array_reduce($data, function ($result, $item) {
    $key = $item['name'] . '-' . $item['date'];
    if (!isset($result[$key])) {
        $result[$key] = 0;
    }
    $result[$key]++;
    return $result;
}, []);

print_r($groupedData);

Keywords

grouping counting data PHP arrays criteria

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