Sort an associative array in php with multiple condition - php

Question

Consider following array
$details = array(
array('lname'=>'A', 'fname'=>'P','membkey'=>700,'head'=>'y'),
array('lname'=>'B', 'fname'=>'Q','membkey'=>540,'head'=>'n'),
array('lname'=>'C', 'fname'=>'R','membkey'=>700,'head'=>'n'),
array('lname'=>'D', 'fname'=>'S','membkey'=>540,'head'=>'y'),
array('lname'=>'E', 'fname'=>'T','membkey'=>700,'head'=>'n')
);
Here I would like to sort with head and membkey. Top element of same membkey element should have 'head=y' and echoed as,
$details = array(
array('lname'=>'A', 'fname'=>'P','membkey'=>700,'head'=>'y'),
array('lname'=>'E', 'fname'=>'T','membkey'=>700,'head'=>'n'),
array('lname'=>'C', 'fname'=>'R','membkey'=>700,'head'=>'n'),
array('lname'=>'D', 'fname'=>'S','membkey'=>540,'head'=>'y'),
array('lname'=>'B', 'fname'=>'Q','membkey'=>540,'head'=>'n')
);
I tried it as follows
function orderbymemberKey( $a, $b ){
if ( $a[membkey] == $b[membkey] )
return 0;
return($a[membkey] < $b[membkey] )? -1 :1;
}
usort( $details, orderbymemberKey );
and it successfully order by membkey.
Any suggestions please.

Answer 1

You're half way there (though you were sorting backwards for membkey based on your example):
function order_by_member_key($a, $b)
{
if ($a['membkey'] == $b['membkey'])
{
// membkey is the same, sort by head
if ($a['head'] == $b['head']) return 0;
return $a['head'] == 'y' ? -1 : 1;
}
// sort the higher membkey first:
return $a['membkey'] < $b['membkey'] ? 1 : -1;
}
usort($details, "order_by_member_key");

Answer 2

Is this array being pulled from a database? Because, if so, you should be able to make use of ORDER BY clauses to clean it up outside of php.

Answer 3

<?php
$membkey = array();
$head = array();
foreach ($details as $key => $row) {
$membkey[$key] = $row['membkey'];
$head[$key] = $row['head'];
}
array_multisort($membkey, SORT_DESC, $head, SORT_DESC, $details);
print_r($details);
Or, an even more generic solution:
function sort_by($array) {
$arguments = func_get_args();
$array = array_pop($arguments);
$variables = array();
foreach ($arguments as $index => $key) {
$variables[] = '$arguments['.$index.']';
if ($index % 2 == 0) {
$arguments[$index] = array();
foreach ($array as $row) $arguments[$index][] = $row[$key];
}
}
// call_user_func_array will not work in this case
eval('array_multisort('.implode(', ', $variables).', $array);');
return $array;
}
print_r(sort_by('membkey', SORT_DESC, 'head', SORT_DESC, $details));

Answer 4

Ugly but someone wrote a function on php.net:
http://php.net/manual/en/function.sort.php
<?php
$array[0]['name'] = 'Chris';
$array[0]['phone'] = '3971095';
$array[0]['year'] = '1978';
$array[0]['address'] = 'Street 1';
$array[1]['name'] = 'Breanne';
$array[1]['phone'] = '3766350';
$array[1]['year'] = '1990';
$array[1]['address'] = 'Street 2';
$array[2]['name'] = 'Dusty';
$array[2]['phone'] = '1541120';
$array[2]['year'] = '1982';
$array[2]['address'] = 'Street 3';
function multisort($array, $sort_by, $key1, $key2=NULL, $key3=NULL, $key4=NULL, $key5=NULL, $key6=NULL){
// sort by ?
foreach ($array as $pos => $val)
$tmp_array[$pos] = $val[$sort_by];
asort($tmp_array);
// display however you want
foreach ($tmp_array as $pos => $val){
$return_array[$pos][$sort_by] = $array[$pos][$sort_by];
$return_array[$pos][$key1] = $array[$pos][$key1];
if (isset($key2)){
$return_array[$pos][$key2] = $array[$pos][$key2];
}
if (isset($key3)){
$return_array[$pos][$key3] = $array[$pos][$key3];
}
if (isset($key4)){
$return_array[$pos][$key4] = $array[$pos][$key4];
}
if (isset($key5)){
$return_array[$pos][$key5] = $array[$pos][$key5];
}
if (isset($key6)){
$return_array[$pos][$key6] = $array[$pos][$key6];
}
}
return $return_array;
}
//usage (only enter the keys you want sorted):
$sorted = multisort($array,'year','name','phone','address');
print_r($sorted);
//output:
Array ( [0] => Array ( [year] => 1978 [name] => Chris [phone] => 3971095 [address] => Street 1 ) [2] => Array ( [year] => 1982 [name] => Dusty [phone] => 1541120 [address] => Street 3 ) [1] => Array ( [year] => 1990 [name] => Breanne [phone] => 3766350 [address] => Street 2 ) )