PHP: Iterating Through a multidimensional Array (4D) - php

Question

I have a multidimensional array structured like below. It mimics a file structure that is storing files based on ./YEAR/MONTH/DAY/FILE.
Array
(
[2019] => Array
(
[05] => Array
(
[12] => Array
(
[0] => default.md
)
)
[12] => Array
(
[22] => Array
(
[0] => default.md
)
)
)
[2020] => Array
(
[05] => Array
(
[19] => Array
(
[0] => default.md
)
)
)
)
I am trying to loop through the entire array and get the values for each specific file while also getting the associated YEAR, MONTH and DAY for that specified file.
My loop is way off as I am trying to nest multiple foreach loops inside of a for loop. The further down the rabbit hole I get, the more issues I encounter
$post_search = directoryArrayMap("content"); //function that creates the array
$year = array_keys($post_search);
for($i = 0; $i < count($post_search); $i++ ) {
echo $year[$i] . "<br>";
foreach($post_search[$year[$i]] as $month => $day ) {
echo $month[$i] . "<br>";
foreach($post_search[$key[$month[$i]]] as $day => $post_file ) {
echo $day . "<br>";
}
}
}
I am looking for the best way to iterate through a multidimensional array. Thanks. My desired output would be something like:
File A:
Year: 2020
Month: 05
Day: 12
File B:
Year: 2019
Month: 12
Day: 22
File C:
Year: 2019
Month: 05
Day: 19
The goal is to run this in conjunction with another loop that checks "is_file" and display the output.

Answer 1

By using a series of nested foreach with key => value iterators you can get the output you want; the key is not to output the date parts until you get to the bottom of the loops:
foreach ($post_search as $year => $months) {
foreach ($months as $month => $days) {
foreach ($days as $day => $files) {
foreach ($files as $file) {
echo "File $file:\nYear: $year\nMonth: $month\nDay: $day\n";
}
}
}
}
Output (for your sample data):
File default.md:
Year: 2019
Month: 5
Day: 12
File default.md:
Year: 2019
Month: 12
Day: 22
File default.md:
Year: 2020
Month: 5
Day: 19
Demo on 3v4l.org

Answer 2

Using functions to handle the confusing nested aspect should help a lot. By no means is my example a robust solution. And personally, I'd probably put the functions in a class & make it object oriented... but that's definitely not the right solution for every case.
You'll have to adapt this, but hopefully the concept is helpful.
function handleYear($year,$arrOfMonths){
echo $year;
foreach ($arrOfMonths as $month=>$arrOfDays){
handleMonth($month,$arrOfDays);
}
}
function handleMonth($month,$arrOfDays){
echo $month;
foreach ($arrOfDays as $dayOfMonth=>$listOfFiles){
handleDay($dayOfMonth,$listOfFiles);
}
}
//to get started
foreach ($data as $year=>$arrOfMonths){
echo $year;
handleYear($year, $arrOfMonths);
}
You could also modify the sub-functions to accept the parent paramaters. Like handleMonth could also take in the year, then handleYear just passes $year along.
EDIT:
After seeing your desired output... I'd suggest passing the year & month down to the handleDay function. Then handleDay could be something like:
function handleDay($day,$arrOfFiles,$year,$month) use (&$files){
foreach ($arrOfFiles as $index=>$fileName){
$file = ['year'=>$year,'month'=>$month,'day'=>$day];
$files[] = $file;
}
}
You would then need to declare $files = [] outside the function, before declaration of handleDay if I'm not mistaken.
But then you'd just have an array of files that you could work with pretty easily.
Personally, I'd probably toil away for awhile to come up with a cleaner solution (Not fond of the use statement in this case, which I might not even be using correctly). If it's in a class, then you could use $this->files instead of the use (&$files).