Sorting of multidimensional array with with numbers and letters - php

Question

How to sort multidimensional array. This is what my array looks like
[0] => Array
(
[id] => 1
[title] => 3A
[active] => 1
)
[1] => Array
(
[id] => 1
[title] => A
[active] => 1
)
[2] => Array
(
[id] => 1
[title] => 2A
[active] => 1
)
[3] => Array
(
[id] => 1
[title] => B
[active] => 1
)
I have tried several usort methods, but cannot seem to get this to work. I am needing the array sorted so that it will sort by numeric then by alpha numeric like so: A,B,2A,3A.
I am not sure if this would be possible without adding a position field to dictate what order the titles are suppose to be in, or am I missing something here?

Answer 1

You can build a "key" for each item where the digit part is padded on the left with 0s, this way, the sort function can perform a simple string comparison:
$temp = [];
foreach ($arr as $v) {
$key = sscanf($v['title'], '%d%s');
if (empty($key[0])) $key = [ 0, $v['title'] ];
$key = vsprintf("%06d%s", $key);
$temp[$key] = $v;
}
ksort($temp);
$result = array_values($temp);
demo
This technique is called a "Schwartzian Transform".

Answer 2

As #Kargfen said, you can use usort with your custom function. Like this one :
usort($array, function(array $itemA, array $itemB) {
return myCustomCmp($itemA['title'], $itemB['title']);
});
function myCustomCmp($titleA, $titleB) {
$firstLetterA = substr($titleA, 0, 1);
$firstLetterB = substr($titleB, 0, 1);
//Compare letter with letter or number with number -> use classic sort
if((is_numeric($firstLetterA) && is_numeric($firstLetterB)) ||
(!is_numeric($firstLetterA) && !is_numeric($firstLetterB)) ||
($firstLetterA === $firstLetterB)
) {
return strcmp($firstLetterA, $firstLetterB);
}
//Letters first, numbers after
if(! is_numeric($firstLetterA)) {
return -1;
}
return 1;
}
This compare-function is just based on the first letter of your titles, but it can do the job ;-)

Answer 3

You can resolve that problem with help of usort and custom callback:
function customSort($a, $b)
{
if ($a['id'] == $b['id']) {
//if there is no number at the beginning of the title, I add '1' to temporary variable
$aTitle = is_numeric($a['title'][0]) ? $a['title'] : ('1' . $a['title']);
$bTitle = is_numeric($b['title'][0]) ? $b['title'] : ('1' . $b['title']);
if ($aTitle != $bTitle) {
return ($aTitle < $bTitle) ? -1 : 1;
}
return 0;
}
return ($a['id'] < $b['id']) ? -1 : 1;
}
usort($array, "customSort");
At first the function compares 'id' values and then if both items are equal it checks 'title' values.