How do you sort an array of objects?

[Phil Powell]

The PHP Manual offered me NO help on this one, so now I appeal to the
populace:

[PHP]
$dirID = @opendir('/my/path/to/files');
while (($fyl = @readdir($dirID ))) {
$obj =& new ClassObject($fy l);
array_push($ima geArray, $obj);
$obj = null;
}
[/PHP]

I now have an array $imageArray of objects as so:

$imageArray[0]->image_name

$imageArray[0]->image_dimensions

I need to sort $imageArray by "image_name " or by "image_dimensio ns"
and I can't think of a way to do it, any ideas?

Thanx
Phil

[Cameron]

Re: How do you sort an array of objects?

Phil Powell wrote:[color=blue]
> The PHP Manual offered me NO help on this one, so now I appeal to the
> populace:
>
> [PHP]
> $dirID = @opendir('/my/path/to/files');
> while (($fyl = @readdir($dirID ))) {
> $obj =& new ClassObject($fy l);
> array_push($ima geArray, $obj);
> $obj = null;
> }
> [/PHP]
>
> I now have an array $imageArray of objects as so:
>
>

$imageArray[0]->image_name

>

$imageArray[0]->image_dimensions

>
> I need to sort $imageArray by "image_name " or by "image_dimensio ns"
> and I can't think of a way to do it, any ideas?
>
> Thanx
> Phil[/color]

have a look at the user comments in the PHP Manual on the pages about
array sorting including...

http://uk2.php.net/manual/en/function.asort.php

~Cameron

[Phil Powell]

Re: How do you sort an array of objects?

asort() does not do anything that I would want since I do not want the
key-val association to be retained. I looked into usort() but that
failed because the callback function that usort calls never gets
called...

$functionBundle Array[0] = get_class($this );
$functionBundle Array[1] = 'field_name_sor t';
usort($imageArr ay, $functionBundle Array, $fieldName);

....

function field_name_sort (&$a, &$b, $fieldName) {
return strcmp(strtolow er($a->$fieldName),
strtolower($b->$fieldName)) ;
}

Problem is that $a and $b need to be compared by index, and I have
absolutely NO idea how to do that since usort() doesn't allot for
using any index at all.

Phil

Cameron <foo@bar.invali d> wrote in message news:<c00ijv$f0 1$1@news6.svr.p ol.co.uk>...[color=blue]
> Phil Powell wrote:[color=green]
> > The PHP Manual offered me NO help on this one, so now I appeal to the
> > populace:
> >
> > [PHP]
> > $dirID = @opendir('/my/path/to/files');
> > while (($fyl = @readdir($dirID ))) {
> > $obj =& new ClassObject($fy l);
> > array_push($ima geArray, $obj);
> > $obj = null;
> > }
> > [/PHP]
> >
> > I now have an array $imageArray of objects as so:
> >
> >

$imageArray[0]->image_name

> >

$imageArray[0]->image_dimensions

> >
> > I need to sort $imageArray by "image_name " or by "image_dimensio ns"
> > and I can't think of a way to do it, any ideas?
> >
> > Thanx
> > Phil[/color]
>
> have a look at the user comments in the PHP Manual on the pages about
> array sorting including...
>
> http://uk2.php.net/manual/en/function.asort.php
>
> ~Cameron[/color]

[Pedro Graca]

Re: How do you sort an array of objects?

Phil Powell wrote:[color=blue]
> asort() does not do anything that I would want since I do not want the
> key-val association to be retained. I looked into usort() but that
> failed because the callback function that usort calls never gets
> called...
>
> $functionBundle Array[0] = get_class($this );
> $functionBundle Array[1] = 'field_name_sor t';
> usort($imageArr ay, $functionBundle Array, $fieldName);[/color]
usort takes /two/ parameters

http://www.php.net/usort

[color=blue]
> function field_name_sort (&$a, &$b, $fieldName) {
> return strcmp(strtolow er($a->$fieldName),
> strtolower($b->$fieldName)) ;
> }[/color]
the callback function takes /two/ parameters.
[color=blue]
> Problem is that $a and $b need to be compared by index, and I have
> absolutely NO idea how to do that since usort() doesn't allot for
> using any index at all.[/color]
So you need to pass a /third/ parameter to the callback function?

Use a global variable :-)



something like this:

#v+
<?php
function user_sort($a, $b) {
global $GLOBAL_VARIABL E_USED_FOR_USER _SORT;

// get a better *local* name :-)
$x = $GLOBAL_VARIABL E_USED_FOR_USER _SORT;
if ($a->$x == $b->$x) return 0;
return ($a->$x < $b->$x) ? -1 : 1;
}

function show($a, $title='') {
echo "$title:\n" ;
foreach ($a as $k=>$v) {
echo "[$k]";
foreach ($v as $kk=>$vv) echo " $kk = $vv;";
echo "\n";
}
echo "\n\n";
}

$a[0]->fullname = 'Zapotec'; $a[0]->age = 30;
$a[1]->fullname = 'Michael'; $a[1]->age = 80;
$a[2]->fullname = 'Abigail'; $a[2]->age = 17;

show($a);

$GLOBAL_VARIABL E_USED_FOR_USER _SORT = 'fullname';
usort($a, 'user_sort');
show($a, 'sorted by fullname');

$GLOBAL_VARIABL E_USED_FOR_USER _SORT = 'age';
usort($a, 'user_sort');
show($a, 'sorted by age');

echo "\n\n";
?>
#v-
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[Chung Leong]

Re: How do you sort an array of objects?

uksort()

Uzytkownik "Phil Powell" <soazine@erols. com> napisal w wiadomosci
news:1cdca2a7.0 402061431.1b699 2fc@posting.goo gle.com...[color=blue]
> asort() does not do anything that I would want since I do not want the
> key-val association to be retained. I looked into usort() but that
> failed because the callback function that usort calls never gets
> called...
>
> $functionBundle Array[0] = get_class($this );
> $functionBundle Array[1] = 'field_name_sor t';
> usort($imageArr ay, $functionBundle Array, $fieldName);
>
> ...
>
> function field_name_sort (&$a, &$b, $fieldName) {
> return strcmp(strtolow er($a->$fieldName),
> strtolower($b->$fieldName)) ;
> }
>
> Problem is that $a and $b need to be compared by index, and I have
> absolutely NO idea how to do that since usort() doesn't allot for
> using any index at all.
>
> Phil
>
> Cameron <foo@bar.invali d> wrote in message[/color]
news:<c00ijv$f0 1$1@news6.svr.p ol.co.uk>...[color=blue][color=green]
> > Phil Powell wrote:[color=darkred]
> > > The PHP Manual offered me NO help on this one, so now I appeal to the
> > > populace:
> > >
> > > [PHP]
> > > $dirID = @opendir('/my/path/to/files');
> > > while (($fyl = @readdir($dirID ))) {
> > > $obj =& new ClassObject($fy l);
> > > array_push($ima geArray, $obj);
> > > $obj = null;
> > > }
> > > [/PHP]
> > >
> > > I now have an array $imageArray of objects as so:
> > >
> > >

$imageArray[0]->image_name

> > >

$imageArray[0]->image_dimensions

> > >
> > > I need to sort $imageArray by "image_name " or by "image_dimensio ns"
> > > and I can't think of a way to do it, any ideas?
> > >
> > > Thanx
> > > Phil[/color]
> >
> > have a look at the user comments in the PHP Manual on the pages about
> > array sorting including...
> >
> > http://uk2.php.net/manual/en/function.asort.php
> >
> > ~Cameron[/color][/color]