Optimising php code for list of items - php

Question

I'm using joomla! to output some extra fields into an article. The fields are a list of images (max of 10) which are displayed using backslider jquery plugin.
Here is the code i've used which works:
<div id="bs0" class="backslider">
<ul class="bs-slides">
<?php
$img1 = $this->item->extrafields['image_1'];
$img2 = $this->item->extrafields['image_2'];
$img3 = $this->item->extrafields['image_3'];
$img4 = $this->item->extrafields['image_4'];
$img5 = $this->item->extrafields['image_5'];
$img6 = $this->item->extrafields['image_6'];
$img7 = $this->item->extrafields['image_7'];
$img8 = $this->item->extrafields['image_8'];
$img9 = $this->item->extrafields['image_9'];
$img10 = $this->item->extrafields['image_10'];
?>
<?php if($img1) { ?>
<li><img src="<?php echo $img1; ?>"></li>
<?php } ?>
<?php if($img2) { ?>
<li><img src="<?php echo $img2; ?>"></li>
<?php } ?>
<?php if($img3) { ?>
<li><img src="<?php echo $img3; ?>"></li>
<?php } ?>
<?php if($img4) { ?>
<li><img src="<?php echo $img4; ?>"></li>
<?php } ?>
<?php if($img5) { ?>
<li><img src="<?php echo $img5; ?>"></li>
<?php } ?>
<?php if($img6) { ?>
<li><img src="<?php echo $img6; ?>"></li>
<?php } ?>
<?php if($img7) { ?>
<li><img src="<?php echo $img7; ?>"></li>
<?php } ?>
<?php if($img8) { ?>
<li><img src="<?php echo $img8; ?>"></li>
<?php } ?>
<?php if($img9) { ?>
<li><img src="<?php echo $img9; ?>"></li>
<?php } ?>
<?php if($img10) { ?>
<li><img src="<?php echo $img10; ?>"></li>
<?php } ?>
</ul>
</div>
I'm not a php expert but is there a better way of optimising this code, I'm thinking maybe putting the $img variables into an array and using a foreach loop to output each list item?
A little help wouldn't go a miss :)

Answer 1

Just iterate over them and use the index to reference the array indices:
for ($i = 1; $i <= 10; ++$i) {
if (!empty($this->item->extrafields["image_$i"])) {
echo '<li><img src="', htmlspecialchars($this->item->extrafields["image_$i"]), '"></li>';
}
}
Assuming there are up to 10 items to investigate.

Answer 2

The solution below will avoid evaluating strings, cache's everything you can, to keep your application running smoothly, and keeps your code nice and tidy.
<div id="bs0" class="backslider">
<ul class="bs-slides">
<?php
// Generate length of our image array / store known length of array
$images = 10;
// Loop through images
for( $i = 1; $i <= $images; $i++ ) {
// Store it for optimization sake.
$field = $this->item->extrafields['image_' . $i];
// Check it's not empty
if( !empty( $field ) ) {
// If not, print to browser
printf(
'<li><img src="%s" alt=""></li>',
htmlspecialchars($field)
);
}
}
?>
</ul>
</div>

Answer 3

I think this code will do same thing.
<div id="bs0" class="backslider">
<ul class="bs-slides">
<?php
for($i = 1; $i <= 10; $i++)
{
$img = $this->item->extrafields['image_'.$i]
if($img) { ?>
<li><img src="<?php echo $img; ?>"></li>
<?php }
}
?>
</ul>
</div>