sort array by element[1] & element[2]

Question

I have data like below (final sort) and I need to sort the lines based

on the first element asc and
then by the second element desc and
then by the third element desc

as elements are separated by .

edumate_3rdparty.20110209.1000.hourly.sql
edumate_3rdparty.20110209.0800.hourly.sql
edumate_3rdparty.20101209.Thursday.daily.sql
moodle_acots.20110130.1600.hourly.sql
moodle_acots.20110105.0800.hourly.sql
moodle_tara.20110316.1200.hourly.sql
moodle_tags.20110222.1000.hourly.sql
moodle_tags.20110208.1801.hourly.sql
moodle_will.20110302.1100.hourly.sql
moodle_wollo.20101031.October.4.weekly.sql

how can I do that in php?

Well... are you worried of how fast it will do that ?

Khez
– Khez

2011-04-05 03:40:40 +00:00
Commented Apr 5, 2011 at 3:40 — Khez
– Khez, Commented Apr 5, 2011 at 3:40

Khez · Accepted Answer · 2011-04-05 05:41:14Z

3

Here's an example on how you could sort that data-set.

<?php
$a=array();
$a[]=explode('.','edumate_3rdparty.20110209.1000.hourly.sql');
$a[]=explode('.','edumate_3rdparty.20110209.0800.hourly.sql');
$a[]=explode('.','edumate_3rdparty.20101209.Thursday.daily.sql');
$a[]=explode('.','moodle_acots.20110130.1600.hourly.sql');
$a[]=explode('.','moodle_acots.20110105.0800.hourly.sql');
$a[]=explode('.','moodle_tara.20110316.1200.hourly.sql');
$a[]=explode('.','moodle_tags.20110222.1000.hourly.sql');
$a[]=explode('.','moodle_tags.20110208.1801.hourly.sql');
$a[]=explode('.','moodle_will.20110302.1100.hourly.sql');
$a[]=explode('.','moodle_wollo.20101031.October.4.weekly.sql');
shuffle($a);
// all you need is this function
function special($a, $b){
    if($a[0]!=$b[0])return strcmp($a[0],$b[0]);// asc
    if($a[1]!=$b[1])return strcmp($b[1],$a[1]);// desc
    return strcmp($b[2],$a[2]);// desc
}
usort($a,'special');
// and maybe the above call
echo'<pre>';
foreach($a as $id=>$value)
    $a[$id]=implode('.',$a[$id]);
var_dump($a);
?>

I used Paul's explode idea to get the test scenario going. So thumb's up to him :)

edited Apr 5, 2011 at 5:41

answered Apr 5, 2011 at 3:49

Khez

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5 Comments

Khez Over a year ago

Updated with some implodes to get the strings back to the way they were, although I highly doubt the data wasn't already an array to begin with.

Radek Over a year ago

@Khez: doesn't work as desired. The output gives me "moodle_acots.20110105.0800.hourly.sql", "moodle_acots.20110130.1600.hourly.sql" where it should be the opposite. 20110130 > 20110105

Radek Over a year ago

how can I make it sort by 3rd element if the first two are the same?

Khez Over a year ago

Didn't notice the DESC in your OP. Try if($a[1]!=$b[1])return strcmp($b[1],$a[1]);. Updated. It already sorts by the third element if the first two are the same.

Radek Over a year ago

e x a c t l y as I wanted it. Thank you

Paul · Accepted Answer · 2011-04-05 03:41:16Z

2

First I would make the data into an array using explode. Then i would sort it using usort.

usort enables you to provide the comparison function for the sort.

answered Apr 5, 2011 at 3:41

Paul

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