php display array data in multiple columns by using ceil function - php

Question

For example, I have a array with 8 data. I want to display in this format
$a = array(1,2,3,4,5,6,7,8);
======
1 2
3 4
5 6
7 8
=====
OR array with 11 data
$a = array(1,2,3,4,5,6,7,8,9,10,11);
=========
1 2 3
4 5 6
7 8 9
10 11
=========
Not sure which part i got wrong. Here is my code
$a = array(1,2,3,4,5,6,7,8);
$c = ceil(count($a)/2);
echo "<table>";
for($i=0; $i<$c;$i++){
echo "<tr>";
echo '<td>'.$a[$i].'</td>';
echo '<td>'.$a[$i+1].'</td>';
}
echo "</table>";
However, my data display in this way instead
======
1 2
2 3
3 4
4 5
=====
Basically, I want to display my data from mysql in this format. But before that, I need to test out the ceil function and see if its working. Anyone knows whats wrong with my coding?

Answer 1

Since you have 2 cels per row you need to calculate the actual index. Also don't forget to close the <tr>
for($i=0; $i<$c;$i++){
echo "<tr>";
echo '<td>'.$a[$i * 2].'</td>';
echo '<td>'.$a[$i * 2 + 1].'</td>';
echo '</tr>';
}
Here is a full example of a cleaner solution:
<?php
$a = array(1,2,3,4,5,6,7,8);
$cols = 2;
$c = ceil(count($a) / $cols);
echo "<table>";
for($i = 0; $i < $c; $i++){
echo "<tr>";
for ($col = 0; $col < $cols; $col++) {
$value = isset($a[$i * $cols + $col]) ? $a[$i * $cols + $col] : '';
echo '<td>'. $value .'</td>';
}
echo "</tr>";
}
echo "</table>";

Answer 2

If you increase it manually you have to skip 1 loop every time.
$a = array(1,2,3,4,5,6,7,8,9,10,11);
$size = sizeof($a);
/* Your magic method to determine the total table cols.
*/
$cols = 3;
#$cols = 2;
echo "<table>";
for($i = 0; $i < $size; $i+=$cols){
echo "<tr>";
for($c = 0; $c < $cols; $c++){
if($i+$c >= $size){
break;
}
echo '<td>'.$a[$i+$c].'</td>';
}
echo "</tr>";
}
echo "</table>";
I've used the method of math to determine if it should print or not because it is faster. However, if you have empty indexes in the array you might want to use the isset() method as the whole code in the inner for loop.
if(isset($a[$i+$c])){
echo '<td>'.$a[$i+$c].'</td>';
}