Memory efficiency optimization tips for PHP array intersection and union

PHP array intersection and union operations in large arrays can improve performance through optimization techniques. Techniques include: use the in_array() function to quickly search when intersecting; use the array_intersect() function to compare arrays of similar sizes; use the array_unique() function to remove duplicate elements when union; use operators to get duplicate elements Union.

Memory efficiency optimization tips for PHP array intersection and union

PHP array intersection and union operations are often used in daily development used. However, for large arrays, these operations can be very time-consuming and consume large amounts of memory. In order to optimize performance, we can use the following techniques:

Intersection

• ##Use the in_array() function: If the number of elements in array A is much smaller than array B, we can use the in_array() function to search for each element in array A in array B.

function getIntersect($arrA, $arrB) {
    $result = [];
    foreach ($arrA as $value) {
        if (in_array($value, $arrB)) {
            $result[] = $value;
        }
    }
    return $result;
}

• Use the array_intersect() function: If the two arrays are of similar size, you can use the array_intersect() function .

function getIntersect($arrA, $arrB) {
    return array_intersect($arrA, $arrB);
}

Union

• Use the array_unique() function: If you need to return a non- For repeated unions, you can use the array_unique() function to merge two arrays and remove duplicate elements.

function getUnion($arrA, $arrB) {
    return array_unique(array_merge($arrA, $arrB));
}

• Use operator: If you do not need to return a unique union, you can use the operator and two arrays.

function getUnion($arrA, $arrB) {
    return $arrA + $arrB;
}

Practical case

Consider the following two large arrays:

$arrA = range(1, 100000);
$arrB = range(50001, 150000);

Using the above optimization techniques, we can optimize the intersection and union Computation of:

// 交集（使用 in_array() 函数）
$intersect = getIntersect($arrA, $arrB);

// 并集（使用 array_unique() 函数）
$union = getUnion($arrA, $arrB);

printf("交集大小：%d\n", count($intersect));
printf("并集大小：%d\n", count($union));

With these optimization techniques, we can significantly improve the performance of large array intersection and union operations, thereby avoiding memory exhaustion and improving code efficiency.

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