Counting Items with Identical Fields in a Two‑Dimensional PHP Array

The article explains how to count occurrences of rows that share the same name and age values in a two‑dimensional PHP array.

Original method (manual loop)

First, the sample data is defined:

$data = [
    ['id' => 1, 'name' => 'John', 'age' => 25],
    ['id' => 2, 'name' => 'Jane', 'age' => 30],
    ['id' => 3, 'name' => 'John', 'age' => 28],
    ['id' => 4, 'name' => 'Jane', 'age' => 35],
    ['id' => 5, 'name' => 'John', 'age' => 25],
];

An empty array $statistics is created to store the grouping result.

$statistics = [];

The array is traversed, a composite key $name . '_' . $age is built, and each item is appended to the corresponding group.

foreach ($data as $item) {
    $name = $item['name'];
    $age  = $item['age'];
    $key = $name . '_' . $age;
    if (!isset($statistics[$key])) {
        $statistics[$key] = [];
    }
    $statistics[$key][] = $item;
}

The grouped result is printed:

foreach ($statistics as $key => $group) {
    echo "属性相同的数据（{$key}）有：" . PHP_EOL;
    foreach ($group as $item) {
        echo "ID: {$item['id']}, Name: {$item['name']}, Age: {$item['age']}" . PHP_EOL;
    }
    echo PHP_EOL;
}

The output shows each name_age combination and the rows that belong to it.

Function‑based method

The same task is performed using array_map to build the groups and array_walk to display them.

$statistics = [];
array_map(function ($v) use (&$statistics) {
    $key = $v['name'] . '_' . $v['age'];
    if (!isset($statistics[$key])) {
        $statistics[$key] = [];
    }
    $statistics[$key][] = $v;
}, $data);

array_walk($statistics, function ($group, $key) {
    echo "属性相同的数据（{$key}）有：" . PHP_EOL;
    foreach ($group as $item) {
        echo "ID: {$item['id']}, Name: {$item['name']}, Age: {$item['age']}" . PHP_EOL;
    }
    echo PHP_EOL;
});

Both approaches produce identical results, demonstrating how to group and count records efficiently in PHP.