How to sort string index of php array

Question

I am interested to sort php array index key in ascending order,

I have this array

 (
[462 1 5.300] => 1
[462 9 4.900] => 1
[462 9 4.300] => 1
[462 2 4.800] => 1
[462 6 4.700] => 1
[462 7 4.900] => 1
[462 7 4.700] => 1
[462 8 4.500] => 1
[462 3 4.500] => 1
[462 4 4.700] => 1
[462 3 4.700] => 1
[462 5 4.500] => 1
)

I expect output to be like this after sort

(
[462 1 5.300] => 1
[462 2 4.800] => 1
[462 3 4.500] => 1
[462 3 4.700] => 1
[462 4 4.700] => 1
[462 5 4.500] => 1
[462 6 4.700] => 1
[462 7 4.700] => 1
[462 7 4.900] => 1
[462 8 4.500] => 1
[462 9 4.300] => 1
[462 9 4.900] => 1
)

I want to sort first 3 index which is used as string is it possible ? I have 3 more column in array but I am showing only 3 columns here..

Answer 1

A normal ksort() can do the trick, but if the sorting is to be performed in multiple orders (different orders for different parameter values), this wouldn't work.

You can achieve this with array_multisort(). First you create three (or more, depending on the number of parameters you have) arrays - each containing the parameter values. Then simply pass it to array_multisort() with the corresponding sort flag:

$param1 = $param2 = $param3 = array();

foreach ($data as $key => $value) {
    $parts = explode(' ', $key);
    $param1[] = $parts[0];
    $param2[] = $parts[1];
    $param3[] = $parts[2];
}

array_multisort($data, $param1, SORT_ASC, $param2, SORT_ASC, $param3, SORT_ASC);

If you want the sorting to be performed in descending order, then you can use SORT_DESC instead. See the documentation for a list of available sort flags.

Demo

Answer 2

The function usort() would be the answer, but you need to sort by key, not by value. So you'd have to use uksort().

Tiny help for you (not tested):

<?php
function cmp($a, $b)
{
    $aParts = explode(' ',$a);
    $bParts = explode(' ',$b);
    if($aParts[0] !== $bParts[0]) {
      return ($aParts[0] >= $bParts[0]) ? -1 : 1;
    }
    if( (int) $aParts[1] !== (int) $bParts[1]) { // compare second parts as integer
      return ($aParts[1] >= $bParts[1]) ? -1 : 1;
    }
    if( (float) $aParts[2] !== (float) $bParts[2]) {
      return ($aParts[2] >= $bParts[2]) ? -1 : 1;        
    }
    return 0;
}

$a = array(
[462 1 5.300] => 1
[462 9 4.900] => 1
[462 9 4.300] => 1
[462 2 4.800] => 1
[462 6 4.700] => 1
[462 7 4.900] => 1
[462 7 4.700] => 1
[462 8 4.500] => 1
[462 3 4.500] => 1
[462 4 4.700] => 1
[462 3 4.700] => 1
[462 5 4.500] => 1
);

uksort($a, "cmp");

foreach ($a as $key => $value) {
    echo "$key: $value\n";
}

Answer 3

In order to get the output you are showing, you can use the ksort() function -http://www.php.net/manual/fr/function.ksort.php.

<?php
$test = array(
"462 1 5.300" => 1,
"462 9 4.900" => 1,
"462 9 4.300" => 1,
"462 2 4.800" => 1,
"462 6 4.700" => 1,
"462 7 4.900" => 1,
"462 7 4.700" => 1,
"462 8 4.500" => 1,
"462 3 4.500" => 1,
"462 4 4.700" => 1,
"462 3 4.700" => 1,
"462 5 4.500" => 1
);

print_r($test);
ksort($test);
print_r($test);
?>