Pattern in while loop - php

Question

<table>
while ($row = mysql_fetch_assoc($result)) {
<tr>
<td>
echo $row['test'] . " " . ' ($' . $row['test2'] . ")<br>";
</td>
</tr>
}
</table>
How do I make a pattern for the background color? For ex, grey, blue, grey blue.

Answer 1

There are multiple ways of doing this. Here is one.
<table>
<?php $i = 0; ?>
<?php while ($row = mysql_fetch_assoc($result)): ?>
<tr<?php echo (++$i & 1 == 1) ? ' class="odd"' : '' ?>>
<td>
<?php echo $row['test'] . " " . ' ($' . $row['test2'] . ") ?><br>
</td>
</tr>
<?php endwhile; ?>
</table>
I suggest giving a CSS class (I've called it "odd" here) to every second row rather than both odd and even. Then you just do:
tr td { background: grey; }
tr.odd td { background: blue; }
in CSS.

Answer 2

You need something like a state variable, where you store wheter the last row was blue or grey. Then you print out the other color and update the state variable for the next pass.
This is one example:
<?php
echo '<table>';
$state = 1;
while ($row = mysql_fetch_assoc($result)) {
echo '<tr>';
if( $state%2 == 0 )
echo '<td style="background-color:grey;">';
else
echo '<td style="background-color:blue;">';
echo $row['test'] . " " . ' ($' . $row['test2'] . ")<br>";
echo '</td></tr>';
$state++;
}
echo '</table>';
?>

Answer 3

If it's a 2 colour pattern, use a variable to switch between blue and grey. if more than 2 colours, use a rotating counter
2 colours
$blue = true;
<table>
while ($row = mysql_fetch_assoc($result)) {
<tr>
<td color="<?php echo $blue?'blue':'grey'; $blue ^= true; ?>">
echo $row['test'] . " " . ' ($' . $row['test2'] . ")<br>";
</td>
</tr>
}
</table>
More than 2 colours, the general solution:
$colourIndex = 0;
$colours = ('blue', 'red', 'green');
...
...
<td color="<?php echo $colours[$colourIndex]; $colourIndex = ($colourIndex+1)%length($colours); ?>">

Answer 4

You can also use the InfiniteIterator to repeat the sequence again and again. This, like the "rotating counter", works for an arbitrary amount of elements.
$props = new InfiniteIterator(
new ArrayIterator(array('a', 'b', 'c','d', 'e'))
); $props->rewind();
$l = rand(10, 20); // or whatever
for ($i=0; $i<$l; $i++) {
$p = $props->current(); $props->next();
echo 'class="', $p, '"... ';
}