array_multisort with 2d array

HeidiR

Hello all,

I'm trying to use array_multisort with a 2d array (code below). I have a simple example below which produces the following incorrect results:

0) b -> 2
1) a -> 1
2) c -> 3

0) 2 -> b
1) 1 -> a
2) c -> 3

What am I missing???

Thanks,

HeidiR

<?php

$ar[0][0] = "b";
$ar[1][0] = "a";
$ar[2][0] = "c";
$ar[0][1] = "2";
$ar[1][1] = "1";
$ar[2][1] = "3";

for($i = 0; $i <= count($ar) -1; $i++) {
echo ($i . ") " . $ar[$i][0] . " -> " . $ar[$i][1] . "<br />");
}

echo ("<br />");

array_multisort($ar[0], SORT_ASC, SORT_STRING, $ar[1], SORT_ASC, SORT_STRING);

for($i = 0; $i <= count($ar) -1; $i++) {
echo ($i . ") " . $ar[$i][0] . " -> " . $ar[$i][1] . "<br />");
}

laserlight

Your array is actually:

$ar = array(array("b", "2"), array("a", "1"), array("c", "3"));

As such, I suggest using [man]usort/man instead:

usort($ar, create_function('$a,$b', 'return strcmp($a[0],$b[0]);'));

HeidiR

laserlight;10888412 wrote:
Your array is actually:
$ar = array(array("b", "2"), array("a", "1"), array("c", "3"));
As such, I suggest using [man]usort/man instead:
usort($ar, create_function('$a,$b', 'return strcmp($a[0],$b[0]);'));

Thanks for your help. Worked perfectly! 🙂

HeidiR

I have a 2d array with numeric values. The usort and _ncmp functions below sort the numeric values correctly.

usort($ar, '_ncmp')

function _ncmp($a, $b) {
if($a[0] < $b[0]) //col1
return -1;
else
return 1;
}

Is there a way to call _ncmp from usort with an argument to dynamically change the sort column? Something like:

function _ncmp($a, $b, $sort_col) {
if($sort_col] < $b[$sort_col])
return -1;
else
return 1;
}