Creating an associative multidimensional array in PHP - php

Question

I'm trying to create an array where the Month is the key and each key contains one or more dates within them. I start with an array that looks like $arr below. Sidenote: I do not control how the original array is structured as it comes from an API. I merely added the below $arr to illustrate and make it easier for people to understand and debug.
$arr = array(
0 => array(
'date' => '2020-12-07'
),
1 => array(
'date' => '2020-12-19'
),
2 => array(
'date' => '2021-01-03'
),
3 => array(
'date' => '2020-01-18'
)
);
Because I need to display the dates differently than this, I need to construct an array which contains the Month name and a formated date:
$sorted = array(); // This is the array I will return later.
foreach ( $arr as $day ) {
setlocale(LC_TIME, 'sv_SE');
$month = strftime( '%B', strtotime( $day['date'] ) );
$display_date = trim( strftime( '%e %b', strtotime( $day['date'] ) ) );
}
Everything I've tried doing here so far has failed. I can't even remember all methods to be honest. The last I tried was this (within the foreach()):
array_push($sorted, array(
$month => $display_date
));
The var_dump() of that, generated an enumerated array:
array (size=4)
0 =>
array (size=1)
'December' => string '7 Dec' (length=5)
1 =>
array (size=1)
'December' => string '19 Dec' (length=6)
2 =>
array (size=1)
'Januari' => string '3 Jan' (length=5)
3 =>
array (size=1)
'Januari' => string '18 Jan' (length=6)
What I'm trying to achieve is this:
All $display_date's should sit under its $month key. The $month key must be unique and contain all dates for that month.
Thankful for any help that gets me in the right direction here because I feel like I'm doing something fundamentally wrong.

Answer 1

You are appending new array with month and date every loop, replace array_push() with $sorted[$month][] = $display_date;
foreach ( $arr as $day ) {
setlocale(LC_TIME, 'sv_SE');
$month = strftime( '%B', strtotime( $day['date'] ) );
$display_date = trim( strftime( '%e %b', strtotime( $day['date'] ) ) );
$sorted[$month][] = $display_date;
}
print_r($sorted);
Output:
Array
(
[december] => Array
(
[0] => 7 dec
[1] => 19 dec
)
[januari] => Array
(
[0] => 3 jan
[1] => 18 jan
)
)