Online PHP editor | output for iS8Ih

@ 2019-03-09T16:39:49Z

<?php
function checkOperation(string $operation): ?string
{
  if (!preg_match('/^\d+([a-zA-Z]+)\+\d+([a-zA-Z]+)$/', $operation, $matches)) {
    return null;
  }

  if (array_count_values(str_split($matches[1])) != array_count_values(str_split($matches[2]))) {
    return null;
  }

  return $operation;
}

var_dump(checkOperation('5p+3p')); echo PHP_EOL;
var_dump(checkOperation('5AB+3AB')); echo PHP_EOL;
var_dump(checkOperation('5AB+3BA')); echo PHP_EOL;
var_dump(checkOperation('5p+3q'));

Output for 7.1.25 - 7.1.27, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.28, 8.4.1 - 8.4.14, 8.5.0: string(5) "5p+3p" string(7) "5AB+3AB" string(7) "5AB+3BA" NULL
Output for 8.4.15: /bin/php-8.4.15: /usr/lib/libm.so.6: version `GLIBC_2.38' not found (required by /bin/php-8.4.15) /bin/php-8.4.15: /usr/lib/libm.so.6: version `GLIBC_2.35' not found (required by /bin/php-8.4.15) /bin/php-8.4.15: /usr/lib/libc.so.6: version `GLIBC_2.34' not found (required by /bin/php-8.4.15) /bin/php-8.4.15: /usr/lib/libc.so.6: version `GLIBC_2.38' not found (required by /bin/php-8.4.15)
Process exited with code 1.

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