Sorting Array

[webmasternovis]

Hi all,

Say I have an array with elements like the following:

13,stringhere,anotherstring,1293
15,stringheretwo,anotherstringtwo,3494

Is there anyway I can sort them through a certain part? Eg, could I sort the above alphabetically through the third string along ("anotherstring" and "anotherstringtwo" would be affected).

It's hard to explain what I mean, but I hope you understand what I'm trying to say through the above 🙂

Could anyone help?

Thanks,
Mike

[m_tt]

array_multisort

[webmasternovis]

I've been looking at that but haven't a clue how it works. I looked at the 'Sorting multi-dimensional array' section, but couldn't see how I could apply it to this.

Could anybody give me a hand with this?

Thanks a lot 🙂

[Installer]

// Create a temp array, with corresponding keys:
foreach ($array as $key => $val) {
    $tmp[$key] = $val[2];
}
array_multisort($tmp, SORT_ASC, $array);
// Sorts by "anotherstring" element.

[webmasternovis]

Thanks for the reply. I've now got this...

// Create a temp array, with corresponding keys: 
foreach ($lines as $line_num => $line) { 
    $tmp[$line_num] = $line[5]; 
} 
array_multisort($tmp, SORT_ASC, $lines); 
// Sorts by "anotherstring" element. 


// The original foreach starts here
foreach ($lines as $line_num => $line) {

Have I implemented that correctly?

Thanks a lot,
Mike

[Installer]

Yes, that will work. I assume that, on the real array you're working with, the sixth element of the subarray (key #5) is the one you want to sort by.

[webmasternovis]

Hmmm... it orders them the same as before. Is that last foreach loop I included correct?

Thanks 🙂

[Installer]

Yes, it all looks correct, and should work (and does on my test array). Try changing to SORT_DESC just to see what happens. What type of data is the element your sorting on (integer, string, etc.)?

[webmasternovis]

It's a string, and it doesn't seem to have any effect on the order. Does the $tmp variable need to be added anywhere in the last foreach loop?

[Installer]

Are you sure you're working with a two-dimensional array, and not just a one-dimensional array of comma-separated strings?

The code works; this should demonstrate that:

$lines[] = array(5, 'stringhere5', 'anotherstring5', 'example5', 'etc5', 105);
$lines[] = array(3, 'stringhere3', 'anotherstring3', 'example3', 'etc3', 103);
$lines[] = array(1, 'stringhere1', 'anotherstring1', 'example1', 'etc1', 101);
$lines[] = array(2, 'stringhere2', 'anotherstring2', 'example2', 'etc2', 102);
$lines[] = array(4, 'stringhere4', 'anotherstring4', 'example4', 'etc4', 104);

echo '<pre>';
echo '<b>Array Unsorted:</b><br />';
print_r($lines);  // Show unsorted array.

// Sort array:
foreach ($lines as $line_num => $line) { 
    $tmp[$line_num] = $line[5]; 
} 
array_multisort($tmp, SORT_ASC, $lines); 

echo '<b>Array Sorted by Subarray Index 5:</b><br />';
print_r($lines);  // Show sorted array.
echo '</pre>';

[webmasternovis]

Actually, I think it is a one dimensional array with strings split by commas. Is there anyway to work around that? Is it similar to this?

Thanks for your help 🙂

[Installer]

Loop through the lines with explode() to make a multi-dimensional array. Then you can sort them with array_multisort(). After that if you want the data back into a one-dimesional array of csv lines, use implode().

foreach ($lines as $key => $line) {
    $lines[$key] = explode(',', $line);
    $tmp[$key] = $lines[$key][5];
}

array_multisort($tmp, SORT_ASC, $lines);

foreach ($lines as $key => $line) {
    $lines[$key] = implode(',', $line);
}

[webmasternovis]

Yep, with a bit of tweaking that worked fine! Thanks for all your help 🙂