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<?php function array_column1($input = null, $columnKey = null, $indexKey = null) { // Using func_get_args() in order to check for proper number of // parameters and trigger errors exactly as the built-in array_column() // does in PHP 5.5. $params = func_get_args(); if (!isset($params[0])) { trigger_error('array_column() expects at least 2 parameters, 0 given', E_USER_WARNING); return null; } elseif (!isset($params[1])) { trigger_error('array_column() expects at least 2 parameters, 1 given', E_USER_WARNING); return null; } if (!is_array($params[0])) { trigger_error('array_column() expects parameter 1 to be array, ' . gettype($params[0]) . ' given', E_USER_WARNING); return null; } if (!is_int($params[1]) && !is_string($params[1]) && !(is_object($params[1]) && method_exists($params[1], '__toString')) ) { trigger_error('array_column(): The column key should be either a string or an integer', E_USER_WARNING); return false; } if (isset($params[2]) && !is_int($params[2]) && !is_string($params[2]) && !(is_object($params[2]) && method_exists($params[2], '__toString')) ) { trigger_error('array_column(): The index key should be either a string or an integer', E_USER_WARNING); return false; } $paramsInput = $params[0]; $paramsColumnKey = (string) $params[1]; $paramsIndexKey = (isset($params[2]) ? (string) $params[2] : null); $resultArray = array(); foreach ($paramsInput as $row) { $key = $value = null; $keySet = $valueSet = false; if ($paramsIndexKey !== null && array_key_exists($paramsIndexKey, $row)) { $keySet = true; $key = $row[$paramsIndexKey]; } if (is_array($row) && array_key_exists($paramsColumnKey, $row)) { $valueSet = true; $value = $row[$paramsColumnKey]; } if ($valueSet) { if ($keySet) { $resultArray[$key] = $value; } else { $resultArray[] = $value; } } } return $resultArray; } var_dump( array_column1( array( array( 'a' => null, 'b' => 16, ), ), 'a' ) );