I would like to sort strings in PHP, and the match should be done foremost on the first letters of a substring, then on the letters of the whole the string.
For example, if someone searches do, and the list contains
Adolf
Doe
Done
the result should be
Doe
Done
Adolf
Using the regular sort($array, SORT_STRING) or things like that does not work, Adolf is sorted before the others.
Does someone have an idea how to do that?
usort(array, callback) lets you sort based on a callback.
example (something like this, didn't try it)
usort($list, function($a, $b) {
$posa = strpos(tolower($a), 'do');
$posb = strpos(tolower($b), 'do');
if($posa != 0 && $posb != 0)return strcmp($a, $b);
if($posa == 0 && $posb == 0)return strcmp($a, $b);
if($posa == 0 && $posb != 0)return -1;
if($posa != 0 && $posb == 0)return 1;
});
usort() this can get pretty heavy :)
stripos(), so you are saving CPU time there at the expense of increased memory. On huge lists, it would definitely be worth benchmarking the two styles. On small lists, the difference will be irrelevant.I would use a custom sort:
<?php
$list = ['Adolf', 'Doe', 'Done'];
function searchFunc($needle)
{
return function ($a, $b) use ($needle)
{
$a_pos = stripos($a, $needle);
$b_pos = stripos($b, $needle);
# if needle is found in only one of the two strings, sort by that one
if ($a_pos === false && $b_pos !== false) return 1;
if ($a_pos !== false && $b_pos === false) return -1;
# if the positions differ, sort by the first one
$diff = $a_pos - $b_pos;
# alternatively: $diff = ($b_pos === 0) - ($a_pos === 0)
if ($diff) return $diff;
# else sort by natural case
return strcasecmp($a, $b);
};
}
usort($list, searchFunc('do'));
var_dump($list);
Output:
array(3) {
[0] =>
string(3) "Doe"
[1] =>
string(4) "Done"
[2] =>
string(5) "Adolf"
}
Odometer will be listed before Abdomen, which may or may not be desirable.$diff check and return would remove that behavior.don't begin with $needle sorted by alphabet.$diff = ($b_pos === 0) - ($a_pos === 0); would be sufficient if he's expecting the behavior you describe.You could order the strings based on stripos($str, $search) so that the ones in the front (stripos() == 0) will come up first.
The following code pushes the substring positions of the search string into a separate array and then uses array_multisort() to apply the proper ordering to the matches; doing it this way rather than usort() avoids having to call stripos() many times.
$k = array_map(function($v) use ($search) {
return stripos($v, $search);
}, $matches);
// $k contains all the substring positions of the search string for all matches
array_multisort($k, SORT_NUMERIC, $matches, SORT_STRING);
// $matches is now sorted against the position
$search. stripos() will return false, which is equated with 0. (Easily rectified if array map returns a huge number instead of false.)SELECT ... WHERE name LIKE '%$string%', in which case your answer would be sufficient. I was just pointing it out for the sake of completeness.In modern PHP, writing two rules can be done more concisely than in the past.
Order by:
do -- false evaluations come before true evaluationsCode: (Demo)
$array = [
'Adolf',
'Doe',
'adept',
'Done',
'dear',
'adopt',
'Deer'
];
$startsWith = 'do';
usort(
$array,
fn($a, $b) =>
(stripos($a, $startsWith) !== 0) <=> (stripos($b, $startsWith) !== 0)
?: strcasecmp($a, $b)
);
var_export($array);
More efficiently (because fewer iterated function call are made) than above, I recommend array_multisort(). The final parameter ($array) is the variable that is ultimately modified by the function.
Code: (Demo)
array_multisort(
array_map(fn($v) => stripos($v, $startsWith) !== 0, $array),
$array,
SORT_STRING | SORT_FLAG_CASE,
$array
);
OdometerandAbdomen, how should it be sorted?