| Re: sort array of objects by muliple values [message #172031 is a reply to message #172030] |
Thu, 27 January 2011 23:21   |
Denis McMahon
Messages: 634
Registered: September 2010
Karma:
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Senior Member |
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On 27/01/11 23:11, Denis McMahon wrote:
> <?php
>
> class User {
> private $firstname;
> private $surname;
> private $birthday;
>
> function __construct($firstname, $surname, $birthday) {
> $this->firstname = $firstname;
> $this->surname = $surname;
> $this->birthday = $birthday;
> }
> function __get($n) {
> return $this->$n;
> }
> }
>
> $sortparams = array("birthday" => "desc", "surname" => "asc",
> "firstname" => "asc");
>
> function cmp_User($a, $b) {
> global $sortparams;
> foreach ($sortparams as $member => $dir) {
> if ($a->$member == $b->$member) continue;
> if ($dir == "asc") {
> return ($a->$member < $b->$member) ? -1 : 1;
> }
> else if ($dir == "desc") {
> return ($b->$member < $a->$member) ? -1 : 1;
> }
> }
> return 0;
> }
>
> $a = array (
> new User('Michael', 'Jordan', '1950-01-01'),
> new User('Alice', 'Smith', '1960-01-01'),
> new User('Kevin', 'Dilan', '1950-01-01'),
> new User('Fred', 'Jordan', '1950-01-01'),
> new User('John', 'Doe', '1960-01-01'),
> new User('Pete', 'Jones', '1960-01-01'),
> );
>
> print "Before Sort\n===========\n";
>
> foreach ($a as $key => $value) {
> print "Item $key; Name: {$value->surname}, {$value->firstname}; DOB:
> {$value->birthday}\n";
> }
>
> usort($a, "cmp_User");
>
> print "\nAfter Sort\n==========\n";
>
> foreach ($a as $key => $value) {
> print "Item $key; Name: {$value->surname}, {$value->firstname}; DOB:
> {$value->birthday}\n";
> }
>
> ?>
>
> Generates:
>
> Before Sort
> ===========
> Item 0; Name: Jordan, Michael; DOB: 1950-01-01
> Item 1; Name: Smith, Alice; DOB: 1960-01-01
> Item 2; Name: Dilan, Kevin; DOB: 1950-01-01
> Item 3; Name: Jordan, Fred; DOB: 1950-01-01
> Item 4; Name: Doe, John; DOB: 1960-01-01
> Item 5; Name: Jones, Pete; DOB: 1960-01-01
>
> After Sort
> ==========
> Item 0; Name: Doe, John; DOB: 1960-01-01
> Item 1; Name: Jones, Pete; DOB: 1960-01-01
> Item 2; Name: Smith, Alice; DOB: 1960-01-01
> Item 3; Name: Dilan, Kevin; DOB: 1950-01-01
> Item 4; Name: Jordan, Fred; DOB: 1950-01-01
> Item 5; Name: Jordan, Michael; DOB: 1950-01-01
Of course, the more logical place to set up $sortparams would be
immediately before the usort that it referred to.
There's probably a better method to pass the array to the callback
involving writing the callback function as a member of the class, but
I'm not really into writing classes.
Rgds
Denis McMahon
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