Group array into sub arrays of 2 elements, last group missing - php

Question

I fetch data from my database and it returns 6 rows. I loop over them add them to a temporary array and then every 2 iterations I add them to a parent array so I will know have an array with sub arrays grouped by 2. Below, as you can see, I echo out each iteration for 6 results. My grouped array is only showing 2 groups of 2 when it should be 3 groups of 2. What am I doing wrong?
Note: I checked the data and the first 2 groups are correct data, but the last 2 rows are missing.
// group entries into subgroups of 2
$buffer = array();
$entries = array();
for( $i = 0; $i < $journal_entries_count; $i++ )
{
if( $i % 2 == 0 && $i > 0 )
{
$entries[] = $buffer;
unset( $buffer );
$buffer = array();
}
$buffer[] = $journal_entries[ $i ];
echo $i, '<br />';
}
0
1
2
3
4
5
Array
(
[0] => Array
(
[0] => Array
(
[journal_entry_id] => 196
[journal_entry_date] => 2014-10-24 20:01:44
[scoring_type_id] => 1
[score] => 2662.00
[wod_title] => yyyyy
[wod_date] => 2014-09-12
[strength] =>
[repscheme] =>
[benchmark] => Annie
)
[1] => Array
(
[journal_entry_id] => 197
[journal_entry_date] => 2014-10-24 20:01:44
[scoring_type_id] => 1
[score] => 196.00
[wod_title] => yyyyy
[wod_date] => 2014-09-12
[strength] =>
[repscheme] =>
[benchmark] => Badger
)
)
[1] => Array
(
[0] => Array
(
[journal_entry_id] => 195
[journal_entry_date] => 2014-10-24 20:00:19
[scoring_type_id] => 1
[score] => 300.00
[wod_title] => Koala Bear WOD
[wod_date] => 2014-10-21
[strength] =>
[repscheme] =>
[benchmark] => Amanda
)
[1] => Array
(
[journal_entry_id] => 194
[journal_entry_date] => 2014-10-24 20:00:19
[scoring_type_id] => 7
[score] => 5.20
[wod_title] => Koala Bear WOD
[wod_date] => 2014-10-21
[strength] => Back Squat
[repscheme] => 10RM
[benchmark] =>
)
)
)
Solution?
I'm not marking it as a solution yet because I'm not sure it will work in all cases,
but loop at each iteration it never hits the last one.
0 = skip - add
1 = skip - add
2 = add - add
3 = skip - add
4 = add - add
5 = skip - add
I added $journal_entries_count + 1 and the results are now correct.
Thoughts?

Answer 1

If $journal_entries_count is 6, then at the end of your loop, $buffer will contain two rows, but it won't have been added to $entries.
You need to add a final
$entries[] = $buffer;
after the loop. Alternatively, you could use array_chunk:
$entries = array_chunk($journal_entries, 2);

Answer 2

can you try it with some simpler code like this and see how you go.
$entries = array();
$journal_entries[] = 1;
$journal_entries[] = 2;
$journal_entries[] = 3;
$journal_entries[] = 4;
$journal_entries[] = 5;
while (count($journal_entries)){
$entries[] = array_slice($journal_entries,0,2);
$journal_entries = array_slice($journal_entries,2);
}
print_r($entries);

Answer 3

You are missing the last 2 entries because you don't add the buffer from the last loop.
You need to update your code and after the foreach loop, check if the buffer is empty or not. If it's not empty then add it to the final array.
You say that for $journal_entries_count + 1 it works, because you actually run the loop one more time and adds the final buffer from the "true" last loop.
The end code should be something like this:
$buffer = array();
$entries = array();
for( $i = 0; $i < $journal_entries_count; $i++ ) {
if( $i % 2 == 0 && $i > 0 ) {
$entries[] = $buffer;
unset( $buffer );
$buffer = array();
}
$buffer[] = $journal_entries[ $i ];
echo $i, '<br />';
}
// add any leftover buffer data
if(count($buffer) > 0) {
$entries[] = $buffer;
}