Question

I have a PHP Array of Cities and States. I want the end result to be sorted alphabetically by State and then by City.

Start With:

Location[0]['state'] => 'Ohio', 
Location[0]['city'] => 'Columbus', 
Location[1]['state'] => 'Illinois', 
Location[1]['city'] => 'Chicago', 
Location[2]['state'] => 'Ohio', 
Location[2]['city'] => 'Cleveland', 
Location[3]['state'] => 'Illinois', 
Location[3]['city'] => 'Springfield'

The end result should be sorted like this:

Location[0]['state'] => 'Illinois', 
Location[0]['city'] => 'Chicago', 
Location[1]['state'] => 'Illinois', 
Location[1]['city'] => 'Springfield', 
Location[2]['state'] => 'Ohio', 
Location[2]['city'] => 'Cleveland', 
Location[3]['state'] => 'Ohio', 
Location[3]['city'] => 'Columbus'

Answer 1

function a($a,$b){
    if($a['state']>$b['state'])return 1;
    if($a['state']<$b['state'])return -1;
    if($a['city']>$b['city'])return 1;
    if($a['city']<$b['city'])return -1;
    return 0;
}

usort($Location,'a');

as of 5.3:

usort($Location,function($a,$b){
    if($a['state']>$b['state'])return 1;
    if($a['state']<$b['state'])return -1;
    if($a['city']>$b['city'])return 1;
    if($a['city']<$b['city'])return -1;
    return 0;
});

ADDED: it is more easy with strcmp

function a($a,$b){
    $c=strcmp($a['state'],$b['state']);
    if($c)return $c;
    return strcmp($a['city'],$b['city']);
}