Online PHP editor | refs for 9ICTq

<?php function cross_product($array, $value) { $output = array(); foreach ($array as $arr) { foreach ($value as $val) { $output[] = array_merge($arr, array($val)); } } return $output; } $input = "A1 / B2 - C3 + D4 / E5 / E6 C3 + A5"; $parts = preg_split('/(?<=[A-Za-z0-9])\s+(?=[A-IK-Za-ik-z])|\s+([+-])\s+/', $input, -1, PREG_SPLIT_DELIM_CAPTURE); foreach ($parts as &$part) { $part = preg_split('#\s+/\s+#', $part); } $init = array_map(function ($v) { return array($v); }, array_shift($parts)); $outputs = array_reduce($parts, 'cross_product', $init); foreach ($outputs as $output) { echo implode(' ', $output) . "\n"; }