PHP Sorting results of a Loop and displaying onscreen - php

Question

I was wondering if someone could point me in the right direction with a coding issue Im having.
I am running a while loop in PHP comparing a post code to another and each run of the loop generates distance data. What Id like to do is then sort this data and display it.
Usually I'd throw everything into a MySQL database then sort that way but I think thats over kill.
Here's an example of the loop :
while($row = mysql_fetch_array($result))
{
$info = get_driving_information($_POST['customerpostcode'], $row[instructor_postcode]);
echo $row['instructor_name'] . " - " . $info['distance'];
}
I know this is probably PHP 101 but Ive never had to do anything like this before and am not sure how.
Thanks in advance for reading,
Rik

Answer 1

I think this is what you mean:
$rows = array();
while($row = mysql_fetch_array($result))
{
$info = get_driving_information($_POST['customerpostcode'], $row[instructor_postcode]);
$row['distance'] = $info['distance']; // store it in the array
$rows[] = $row;
}
Then use usort to sort the $rows array by the distance key.

Answer 2

What I'd recommend here is storing each distance result in an array and then apply a sort to the array. For example:
$distances = array();
while($row = mysql_fetch_array($result))
{
$info = get_driving_information($_POST['customerpostcode'], $row[instructor_postcode]);
$distances[$info['distance']] = $row['instructor_name'] . " - " . $info['distance'];
}
if(ksort($distances)) {
foreach($distances as $key=>$value) {
echo $value;
}
}
Note that my solution will not work for you if an exact distance appears more than once in the array; If that seems likely then you might need a different array-based solution.
For more information on array sorting, see Sorting Arrays in the PHP manual.

Answer 3

$data = array();
while($row = mysql_fetch_assoc($result)) {
$info = get_driving_information($_POST['customerpostcode'], $row['instructor_postcode']);
$data[$row['instructor_name']] = $info['distance'];
}
asort($data);
foreach ($data as $instructor => $distance) echo "$instructor - $distance<br />\n";
This will sort by instructor name. If you need to sort by distance, just reverse the way data is stored in the temporary array, I.E. $data[$row['distance']] = $info['instructor_name'];.
This will not work if the value you use as the temporary array key appears more than once, for that you would have to use array_multisort().
$data = $instructors = $distances = array();
for ($i = 0; $row = mysql_fetch_assoc($result); $i++) {
$info = get_driving_information($_POST['customerpostcode'], $row['instructor_postcode']);
$instructors[$i] = $row['instructor_name'];
$distances[$i] = $row['distance'];
$data[$i] = array('instructor'=>$row['instructor_name'],'distance'=>$info['distance']);
}
array_multisort($instructors,SORT_DESC,$distances,SORT_ASC,$data);
foreach ($data as $entry) echo "{$entry['instructor']} - {$entry['distance']}<br />\n";

Answer 4

This will work even if you have same instructor_name or distances several time in the array. Additionally buy modifying cmp() function you can sort whole thing by any other criteria.
$drivers = array();//initialising an array
while($row = mysql_fetch_array($result))
{
$info = get_driving_information($_POST['customerpostcode'], $row[instructor_postcode]);
$drivers[]=row;//adding new item to array
}
$drivers = usort($drivers,'cmp'); // sorting array using custom comparison function "cmp()"
foreach ($drivers as $driver) //printing results
echo $driver['instructor_name'] . " - " . $driver['distance'];
//custom comparison function
function cmp($a, $b) //returns +1 if $a > $b, -1 if $a < $b, else returns 0
{
if ($a['distance']>$b['distance'])
return 1;
if ($a['distance']<$b['distance'])
return -1;
return 0;
//quicker solution is to "return $a['distance']-$b['distance'];"
}