Sorting an array of multi-disk arrays into more than one "column" (key) with the specified sorting options

Question

I am looking to be able to sort an array of multidimensional arrays on multiple columns. To complicate this even further, I would like to be able to set certain sorting options for each key / column. I have something that looks like the result of a database query, but it doesn't really come from one, so you need to sort it in PHP, not SQL.

Array ( [0] => Array ( [first_name] => Homer [last_name] => Simpson [city] => Springfield [state] => Unknown [zip] => 66735 ) [1] => Array ( [first_name] => Patty [last_name] => Bouvier [city] => Scottsdale [state] => Arizona [zip] => 85250 ) [2] => Array ( [first_name] => Moe [last_name] => Szyslak [city] => Scottsdale [state] => Arizona [zip] => 85255 ) [3] => Array ( [first_name] => Nick [last_name] => Riviera [city] => Scottsdale [state] => Arizona [zip] => 85255 ) ) 

I would like to be able to sort it in the same way that can be done with a DB query. Oh, and sometimes the column / key needs to be indicated by number.

What I had in mind was like this:

 $sortOptions = array( array( 'city', SORT_ASC, SORT_STRING ), array( 'zip', SORT_DESC, SORT_NUMERIC), array( 2, SORT_ASC, SORT_STRING) // 2='last_name' ); $sorter = new MultiSort($data, $sortOptions ); $sortedData = $sorter->getSortedArray() ; print_r( $jmsSorted); 

What I would like to end up with:

 Array ( [0] => Array ( [first_name] => Nick [last_name] => Riviera [city] => Scottsdale [state] => Arizona [zip] => 85255 ) [1] => Array ( [first_name] => Moe [last_name] => Szyslak [city] => Scottsdale [state] => Arizona [zip] => 85255 ) [2] => Array ( [first_name] => Patty [last_name] => Bouvier [city] => Scottsdale [state] => Arizona [zip] => 85250 ) [3] => Array ( [first_name] => Homer [last_name] => Simpson [city] => Springfield [state] => Unknown [zip] => 66735 ) ) 

UPDATE: I think that ideally a solution would lead to a dynamic creation

 array_multisort( $city, SORT_ASC, SORT_STRING, $zip, SORT_DESC, SORT_NUMERIC, $last_name, SORT_ASC, SORT_STRING, $inputArray); 

The problem is that I do not want to "hard code" these key names there. I tried to create a solution based on Example # 3 Sorting database results from array_multisort() documentation, which ended up using array_multisort() but I cannot find a way to use my dynamically constructed argument list for array_multisort() .

My attempt was to "combine" these arguments together into an array, and then

 call_user_func_array( 'array_multisort', $functionArgs); 

This leads to

 Warning: Parameter 2 to array_multisort() expected to be a reference, value given in... 

Answer 1

Here's what I finally settled on the ability to sort multidimensional arrays. Both of the above answers are good, but I was also looking for something flexible.

I definitely don’t think there is any kind of “right” answer, but this is what works for my needs and is flexible.

As you can see from my @link in the _usortByMultipleKeys() comment, it was adapted from a comment in a PHP manual that does not currently exist, but I consider http://www.php.net/manual/en/function.usort .php # 104398 is a new version of the original comment. I have not studied this new sentence.

 /** * Sort the resultSet. * * Usage: $sortOptions = array( * 'section', // Defaults to SORT_ASC * 'row' => SORT_DESC, * 'retail_price' => SORT_ASC); * $results->sortResults($sortOptions); * * @param array $sortOptions An array of sorting instructions */ public function sortResults(array $sortOptions) { usort($this->_results, $this->_usortByMultipleKeys($sortOptions)); } /** * Used by sortResults() * * @link http://www.php.net/manual/en/function.usort.php#103722 */ protected function _usortByMultipleKeys($key, $direction=SORT_ASC) { $sortFlags = array(SORT_ASC, SORT_DESC); if (!in_array($direction, $sortFlags)) { throw new InvalidArgumentException('Sort flag only accepts SORT_ASC or SORT_DESC'); } return function($a, $b) use ($key, $direction, $sortFlags) { if (!is_array($key)) { //just one key and sort direction if (!isset($a->$key) || !isset($b->$key)) { throw new Exception('Attempting to sort on non-existent keys'); } if ($a->$key == $b->$key) { return 0; } return ($direction==SORT_ASC xor $a->$key < $b->$key) ? 1 : -1; } else { //using multiple keys for sort and sub-sort foreach ($key as $subKey => $subAsc) { //array can come as 'sort_key'=>SORT_ASC|SORT_DESC or just 'sort_key', so need to detect which if (!in_array($subAsc, $sortFlags)) { $subKey = $subAsc; $subAsc = $direction; } //just like above, except 'continue' in place of return 0 if (!isset($a->$subKey) || !isset($b->$subKey)) { throw new Exception('Attempting to sort on non-existent keys'); } if ($a->$subKey == $b->$subKey) { continue; } return ($subAsc==SORT_ASC xor $a->$subKey < $b->$subKey) ? 1 : -1; } return 0; } }; } 

Answer 2

In PHP 5.3, each parameter in an array must be a reference when calling array_multisort() with call_user_func_array() .

This function sorts a multidimensional array and shows how to build an array of reference parameters that works correctly.

 function msort() { $params = func_get_args(); $array = array_pop($params); if (!is_array($array)) return false; $multisort_params = array(); foreach ($params as $i => $param) { if (is_string($param)) { ${"param_$i"} = array(); foreach ($array as $index => $row) { ${"param_$i"}[$index] = $row[$param]; } } else ${"param_$i"} = $params[$i]; $multisort_params[] = &${"param_$i"}; } $multisort_params[] = &$array; call_user_func_array("array_multisort", $multisort_params); return $array; } 

Example:

$ data - given array from question

 $sorted_data = msort('city', SORT_ASC, SORT_STRING, 'zip', SORT_DESC, SORT_NUMERIC, $data) 

Answer 3

This should work for the situation described.

 usort($arrayToSort, "sortCustom"); function sortCustom($a, $b) { $cityComp = strcmp($a['city'],$b['city']); if($cityComp == 0) { //Cities are equal. Compare zips. $zipComp = strcmp($a['zip'],$b['zip']); if($zipComp == 0) { //Zips are equal. Compare last names. return strcmp($a['last_name'],$b['last_name']); } else { //Zips are not equal. Return the difference. return $zipComp; } } else { //Cities are not equal. Return the difference. return $cityComp; } } 

You can condense it in one line as follows:

 function sortCustom($a, $b) { return ($cityComp = strcmp($a['city'],$b['city']) ? $cityComp : ($zipComp = strcmp($a['zip'],$b['zip']) ? $zipComp : strcmp($a['last_name'],$b['last_name']))); } 

As for the custom sorting function, you are reinventing the wheel. Take a look at array_multisort() .

Answer 4

You might want to use usort . All you have to do is make functions that tell the sorter how to sort it. Documents have more information on how to do this.