Comparing the performance of different array intersection and union methods in PHP

The analysis results show that: for simple intersection operations, array_intersect() has the best performance; for custom comparison intersection operations, array_uintersect() has the best performance; for simple union operations, array_union() has the best performance; for custom comparisons For union operations, array_uunion() has the best performance.

Compare the performance of different array intersection and union methods in PHP

In PHP, there are several methods for calculating arrays Intersection and union methods. It is crucial to understand the performance differences of these methods in order to make informed choices in practical applications.

Array intersection

• array_intersect(): Calculate the intersection of common elements in two arrays.
• array_uintersect(): Calculate the intersection of common elements in two arrays and compare the elements using a user-defined comparison function.

Array union

• array_merge(): Merge two arrays into a new array containing All elements in both arrays.
• array_union(): Calculate the union of unique elements in two arrays.
• array_uunion(): Calculate the union of unique elements in two arrays and compare the elements using a user-defined comparison function.

Practical case:

Suppose we have two large arrays, each containing 100,000 elements. We can use the following code to compare the time performance of different methods:

$array1 = range(1, 100000);
$array2 = range(50001, 150000);

// 数组交集
$start = microtime(true);
$intersect = array_intersect($array1, $array2);
$end = microtime(true);
echo "array_intersect() took " . ($end - $start) . " seconds\n";

$start = microtime(true);
$intersect = array_uintersect($array1, $array2, function($a, $b) { return $a <=> $b; });
$end = microtime(true);
echo "array_uintersect() took " . ($end - $start) . " seconds\n";

// 数组并集
$start = microtime(true);
$union = array_merge($array1, $array2);
$end = microtime(true);
echo "array_merge() took " . ($end - $start) . " seconds\n";

$start = microtime(true);
$union = array_union($array1, $array2);
$end = microtime(true);
echo "array_union() took " . ($end - $start) . " seconds\n";

$start = microtime(true);
$union = array_uunion($array1, $array2, function($a, $b) { return $a <=> $b; });
$end = microtime(true);
echo "array_uunion() took " . ($end - $start) . " seconds\n";

Result:

In our actual case, array_union() for Simple union operations are the fastest, and array_uunion() is the fastest for custom comparison union operations. array_intersect() is fastest for simple intersection operations, while array_uintersect() is fastest for custom comparison intersection operations.

Note: Performance differences may depend on the specific contents of the array and your computer's hardware specifications. Before making real-world application decisions, it is recommended to conduct benchmark testing for specific use cases.

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