Traversing arrays php - php

Question

I was wondering if there is a better solution to loop through an array from mid to end then from start to mid. Particularly for an associative array.
So for example if there is an associative array with the keys
$dow = array(Mon => etc, Tue => etc, Wed => etc, Thr => etc .. to .. Sun => etc).
I would start searching the array from Thurs to find the next day with something specific which could be anyday but happens to be on Tues, I usually iterate from Thurs (by index) to Sunday then, reset and start again from Monday to Wed and find the target when reaching Tues.
I count the index via an id and when it reaches 6 reset the id to 0
$id = 3 // Found day is Thursday id
//Loop function starts here
$id++; // start search from one day above found day
if ($id >= 6){ //when reaching Sunday
$id = 0 // start search from monday
}
// check array here for that specific thing
So the question is to ask if there is a more simple solution than this, ie split array from index thursday to sunday and add it onto the beginning of the array and then do the loop without having to count an index or if there are any other solutions without using the count index.

Answer 1

You can try with array_splice:
$array = array(1,2,3,4,5,6,7);
$lastDays = array_splice($array, 3);
$firstDays = $array;
print_r(array('first days' => $firstDays, 'last days' => $lastDays));
If the day is not in $lastDays (use a boolean like $matchFound) then you would search in $firstDays.
Or just use with array_merge:
$array = array(1,2,3,4,5,6,7);
$array = array_merge(array_splice($array, 3), $array);
print_r($array);
where output is:
Array
(
[0] => 4
[1] => 5
[2] => 6
[3] => 7
[4] => 1
[5] => 2
[6] => 3
)
and then you can search with a foreach.

Answer 2

maybe a foreach would be more efficient. hope this helps.
$id = 3 // Found day is Thursday id
$i =0;
//Loop function starts here
foreach($dow as $idx)
if($id == $i):
else if($i > $id):
endif;
if($i == count($dow)){$i=0;}else{$i++;}
endforeach;

Answer 3

<?php
$dow = array("mon","tue","wed","thu","fri","sat","sun");
$pick_a_day = 2; // user input; NON zero based. monday = 1
$pick_a_day--; // make it zero based to use in code
foreach($dow as $inc => $an_element )
{
echo $dow[($pick_a_day+(count($dow))) % (count($dow))]." - loop number:".($inc+1)."\n";
$pick_a_day++;
}
?>
output
tue - loop number:1
wed - loop number:2
thu - loop number:3
fri - loop number:4
sat - loop number:5
sun - loop number:6
mon - loop number:7

Answer 4

Maybe not the best solution, but a solution:
function half($array) {
$h = sizeof($array) / 2;
$a1 = array_splice($array, $h);
$a2 = array_splice($array, 0);
$res = array_merge($a1, $a2);
return $res;
}
$dow = array('Mon' => 'etc1', 'Tue' => 'etc2', 'Wed' => 'etc3', 'Thr' => 'etc4', 'Fri' => 'etc5', 'Sat' => 'etc6', 'Sun' => 'etc7');
$b = half($dow);
Now you can go through with a foreach, or how would you like. Result of $b:
Array
(
[Thr] => etc4
[Fri] => etc5
[Sat] => etc6
[Sun] => etc7
[Mon] => etc1
[Tue] => etc2
[Wed] => etc3
)