How to Find Matching Pair from an Array in PHP ?

Given an Array, the task is to find the matching pair from a given array in PHP. Matching a pair from an array involves searching for two elements that satisfy a certain condition, such as having the same value, summing up to a specific target, or meeting some other criteria. Here, we will cover three common scenarios for finding matching pairs in an array.

Finding Pairs with a Specific Sum

To find pairs in an array that add to a specific sum, you can use a nested loop to iterate through the array and check for pairs.

Example:

PHP

<?php

function pairSum($arr, $targetSum) {
    $pairs = [];

    $len = count($arr);

    for ($i = 0; $i < $len - 1; $i++) {
        for ($j = $i + 1; $j < $len; $j++) {
            if ($arr[$i] + $arr[$j] == $targetSum) {
                $pairs[] = [$arr[$i], $arr[$j]];
            }
        }
    }

    return $pairs;
}

// Driver code
$arr = [2, 7, 4, 5, 11, 15];
$sum = 9;
$result = pairSum($arr, $sum);

print_r($result);

?>

Output

Array
(
    [0] => Array
        (
            [0] => 2
            [1] => 7
        )

    [1] => Array
        (
            [0] => 4
            [1] => 5
        )
)

Finding Duplicate Pairs

To find the duplicate pairs (pairs with the same values), you can use nested loops to compare each element with every other element in the array.

Example:

PHP

<?php

function duplicatePairs($arr) {
    $pairs = [];

    $len = count($arr);
    for ($i = 0; $i < $len - 1; $i++) {
        for ($j = $i + 1; $j < $len; $j++) {
            if ($arr[$i] == $arr[$j]) {
                $pairs[] = [$arr[$i], $arr[$j]];
            }
        }
    }

    return $pairs;
}

// Driver sum
$arr = [1, 2, 3, 2, 4, 1];
$res = duplicatePairs($arr);

print_r($res);

?>

Output

Array
(
    [0] => Array
        (
            [0] => 1
            [1] => 1
        )

    [1] => Array
        (
            [0] => 2
            [1] => 2
        )
)

Finding Pairs with a Specific Value

To find pairs with a specific value, you can iterate through the array and check for elements that match the desired value.

Example:

PHP

<?php

function pairsWithValue($arr, $targetValue) {
    $pairs = [];

    foreach ($arr as $value) {
        if (in_array($targetValue - $value, $arr)) {
            $pairs[] = [$value, $targetValue - $value];
        }
    }

    return $pairs;
}

// Driver code
$arr = [3, 1, 4, 6, 5, 2];
$targetVal = 7;

$res = pairsWithValue($arr, $targetVal);

print_r($res);

?>

Output

Array
(
    [0] => Array
        (
            [0] => 3
            [1] => 4
        )

    [1] => Array
        (
            [0] => 1
            [1] => 6
        )

    [2] => Array
        (
     ...