| Re: sort array of objects by muliple values [message #172027 is a reply to message #172019] |
Thu, 27 January 2011 21:27   |
Denis McMahon
Messages: 634
Registered: September 2010
Karma:
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Senior Member |
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On 27/01/11 19:59, Max wrote:
> On Jan 27, 8:10 pm, Jerry Stuckle <jstuck...@attglobal.net> wrote:
>> On 1/27/2011 2:04 PM, Max wrote:
>>
>>> Is there a simple way to sort $array below like SQL it does? I.e.
>>> ORDER BY birthday ASC, name ASC
>>> Output would be Kevin, Michael, Alice
>>
>>> Thanks!
>>
>>> <?php
>>> class User {
>>> private $firstname;
>>> private $surname;
>>> private $birthday;
>>
>>> function __construct($firstname, $surname, $birthday) {
>>> $this->firstname = $name;
>>> $this->surname = $surname;
>>> $this->birthday = $birthday;
>>> }
>>> function __get($n) {
>>> return $this->$n;
>>> }
>>> }
>>
>>> $array = array (
>>> new User('Alice', 'Smith', '1960-01-01'),
>>> new User('Michael', 'Jordan', '1950-01-01'),
>>> new User('Kevin', 'Dilan', '1950-01-01'),
>>> );
>>
>> Use usort() with a static member function. See
>>
>> http://us2.php.net/manual/en/function.usort.php
>>
>> for an example.
>
> it sorts only by one field
The thing with a user defined sort is that you have to write the sort
function yourself, and it can sort on whatever you want it to:
<?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;
}
}
function cmp_User($a, $b)
{
if ($a->birthday == $b->birthday) {
if ($a->surname == $b->surname) {
return 0;
}
return ($a->surname < $b->surname) ? -1 : 1;
}
return ($a->birthday < $b->birthday) ? -1 : 1;
}
$a = array (
new User('Alice', 'Smith', '1960-01-01'),
new User('Michael', 'Jordan', '1950-01-01'),
new User('Kevin', 'Dilan', '1950-01-01'),
);
print "Before Sort\n===========\n";
foreach ($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: Smith, Alice; DOB: 1960-01-01
Item 1; Name: Jordan, Michael; DOB: 1950-01-01
Item 2; Name: Dilan, Kevin; DOB: 1950-01-01
After Sort
==========
Item 0; Name: Dilan, Kevin; DOB: 1950-01-01
Item 1; Name: Jordan, Michael; DOB: 1950-01-01
Item 2; Name: Smith, Alice; DOB: 1960-01-01
Rgds
Denis McMahon
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