Get last element of an array which not null - php

Question

I have a multidimensional array and I would like to find an simple way to return the last occurrence of a key when "time_reported" is not NULL .
Example: for the array below the output should be the key n°2 cause it's the last array when a value is assigned.
array (
0 =>
array (
'point_name' => 'DOGAL',
'time_reported' => '2019-11-14 01:35:00',
),
1 =>
array (
'point_name' => '54/20',
'time_reported' => '2019-11-14 02:10:00',
),
2 =>
array (
'point_name' => '52/30',
'time_reported' => '2019-11-14 02:20:00',
),
3 =>
array (
'point_name' => '49/40',
'time_reported' => NULL,
),
4 =>
array (
'point_name' => '47/50',
'time_reported' => NULL,
),
5 =>
array (
'point_name' => 'PORTI',
'time_reported' => NULL,
),
)
I already had the idea to use a foreach loop to find the last occurrence but I don't know if it's the most efficient way to do that

Answer 1

Using foreach loop we can use array_reverse function so we can reverse the array, looping the last array to first. Then check if the key values is null or empty. You can see the result here.
<?php
$myarrays = array( array (
'point_name' => 'DOGAL',
'time_reported' => '2019-11-14 01:35:00',
),
array (
'point_name' => '54/20',
'time_reported' => '2019-11-14 02:10:00',
),
array (
'point_name' => '52/30',
'time_reported' => '2019-11-14 02:20:00',
),
array (
'point_name' => '49/40',
'time_reported' => NULL,
),
array (
'point_name' => '47/50',
'time_reported' => NULL,
),
array (
'point_name' => 'PORTI',
'time_reported' => NULL,
),
);
#echo "<pre>";
#print_r($myarrays);
foreach ( array_reverse($myarrays) as $array ) {
if($array['time_reported'] !== NULL){
echo $array['point_name']."\n";
echo $array['time_reported'];
break 1; // stop the loop
}
}
?>

Answer 2

If the array is in order, you can just traverse it until $item["time_reported"] is not null. This will get it done in O(N) in the worst case. If the array is not sorted, and you need the earliest / latest time, you will need to look at every element in the array for a best (and every) case of O(N).
$a = array(...);
for ($i = count($a) - 1; $i > 0 && $a[$i]["time_reported"] === null; $i--);
echo "Found at index {$i}\n";

Answer 3

Try this too:
function getLastNotNullValueInArray($array)
{
$reversed = array_reverse($array);
foreach($reversed as $arrValue)
{
if($arrValue)
return $arrValue;
}
return false;
}