Performance‑Optimized Alternatives to Common PHP Functions

In typical PHP development, standard functions are used to solve problems, but the author discovered alternative approaches that can considerably boost performance.

1. Remove Duplicates

Conventional method: array_unique($array); Alternative method: array_keys(array_flip($array)); Benchmark on a 4‑million‑element array with 3‑million duplicates shows array_unique taking 787.31 ms, while the alternative completes in 434.03 ms—about 1.8× faster. This technique works only for simple one‑dimensional arrays because array_flip swaps keys and values.

2. Get Random Array Record

Conventional method: array_rand($array); Alternative method: $array[mt_rand(0, count($array) - 1)]; Testing on a 5‑million‑element array shows array_rand at 25.99 µs versus the mt_rand approach at 0.95 µs, a 27.3× speed gain. The mt_rand function uses the Mersenne Twister algorithm, which has been the default randomizer since PHP 7.1.

3. Test Alphanumeric Characters

Conventional method: preg_match('/^[a-zA-Z0-9]+$/', $string); Alternative method: ctype_alnum($string); On a dataset of over 100 k mixed strings, preg_match required 15.39 ms while ctype_alnum completed in 2.06 ms—approximately 7.5× faster. The same alternative applies to ctype_alpha() and ctype_digit() for alphabetic and numeric checks.

4. Replace Substring

Conventional method: str_replace('a', 'b', $string); Alternative method: strtr($string, 'a', 'b'); Benchmarking with a 5‑million‑element random string array shows str_replace taking 676.59 ms versus strtr at 305.59 ms, a 2.2× improvement. Another method can be up to 2× faster on average.

Other Performance Improvements

Prefer JSON over XML.

Declare variables outside loops instead of inside each iteration.

Avoid function calls in loop headers, e.g., replace for ($i = 0; $i < count($array); $i++) with a cached count.

Reset memory‑consuming variables when appropriate.

Prefer switch statements over multiple if checks.

Use require/include instead of require_once/include_once when opcode caching is ensured.

Even with PHP 7.4, which is already faster than earlier versions, these alternative functions can noticeably improve script execution time. The author provides a GitHub repository (devmount/faster-php) containing all tests and mentions using Bart van Hoekelen's tool for measuring execution time.