Sort an array of objects by fields - php

Question

i would like to sort the following tab by the "date" field and calculate the sum of the "temps" field :
0 => array (size=3) 'id_cra' => string '4586' (length=4) 'temps' => string '03:00:00' (length=8) 'date' => string '2013-06-03' (length=10)
1 => array (size=3) 'id_cra' => string '4587' (length=4) 'temps' => string '03:00:00' (length=8) 'date' => string '2013-06-06' (length=10)
2 => array (size=3) 'id_cra' => string '4588' (length=4) 'temps' => string '03:00:00' (length=8) 'date' => string '2013-06-05' (length=10)
3 => array (size=3) 'id_cra' => string '4589' (length=4) 'temps' => string '03:00:00' (length=8) 'date' => string '2013-06-06' (length=10)
4 => array (size=3) 'id_cra' => string '4590' (length=4) 'temps' => string '03:00:00' (length=8) 'date' => string '2013-06-07' (length=10)
5 => array (size=3) 'id_cra' => string '4591' (length=4) 'temps' => string '02:00:00' (length=8) 'date' => string '2013-06-03' (length=10)
6 => array (size=3) 'id_cra' => string '4592' (length=4) 'temps' => string '03:30:00' (length=8) 'date' => string '2013-06-03' (length=10)
The expected result :
date = > Sum of the "Temps" fields
2013-06-03 =>08:30:00
2013-06-06 =>06:00:00
etc
PS: Sorry for asking something that might be simple for you, i already checked on internet (for instance here : Sort array of objects by object fields) but i don't understand the answer

Answer 1

I didn't try, but it has to be something like this:
$arr = [your array data]; // your array which has to be sorted
usort($arr, 'sort_array');
function sort_array($a, $b) {
$timeA = strtotime($a['date']);
$timeB = strtotime($b['date']);
if($timeA == $timeB) {
return 0;
}
return $timeA < $timeB ? -1 : 1;
}
calculating the sums would be a loop after sorting the array where you have to "group" by date and sum the "temps"

Answer 2

The first part is fairly simple. We can sort the data for an array by a field using array_multisort() like so:
<?php
$data = array(
0 => array('id_cra' => '4586', 'temps' => '03:00:00', 'date' => '2013-06-03'),
1 => array('id_cra' => '4587', 'temps' => '03:00:00', 'date' => '2013-06-06'),
2 => array('id_cra' => '4588', 'temps' => '03:00:00', 'date' => '2013-06-05'),
3 => array('id_cra' => '4589', 'temps' => '03:00:00', 'date' => '2013-06-06'),
4 => array('id_cra' => '4590', 'temps' => '03:00:00', 'date' => '2013-06-07'),
5 => array('id_cra' => '4591', 'temps' => '02:00:00', 'date' => '2013-06-03'),
6 => array('id_cra' => '4592', 'temps' => '03:30:00', 'date' => '2013-06-03')
);
$tmp = array();
foreach($data as $k=>$r){
$tmp[] = $r['date'];
}
array_multisort($tmp,SORT_DESC,$data);
echo '<pre>',print_r($data),'</pre>';
But now want to add the times for each of the days. This isn't difficult, but you will lose the id_cra values. So for the example below I have just created a new array. You should be able to use the information to build it back into your original array if that what you want to do.
date_default_timezone_set('America/New_York'); //set timezone
$midnight = mktime(0,0,0,date("n"),date("j"),date("Y")); // create a constant
$times = array();
foreach($data as $d){
// get number of secs since const
$time = strtotime(date("Y-m-d",$midnight).' '.$d['temps']) - $midnight;
if(isset($times[$d['date']])){
$times[$d['date']] += $time; // if day exists add secs
}else{
$times[$d['date']] = $time; // else set day with cur secs
}
}
foreach($times as $k=>&$time){
$time = date("Y-m-d H:i:s",strtotime($k)+$time); // reformat to date
}
echo '<pre>',print_r($times),'</pre>';