Define the Beginning of a Wordpress Excerpt - wordpress

Question

I am trying to shave off a few characters or pieces of text we have in our posts. We have the date and source from which the story in our posts cam but I would not like that included in our excerpt and the formatting people insist that it must remain at the top of the post.
How would I go about specifying exactly where I would like the excerpt to begin in the post? Could I have it begin at something like <p> tag or could I set the number of characters to skip before it begins?
Any help would be greatly appreciated. Here is my code thus far:
<phpcode>
<?php $my_query = new WP_Query('category_name=science&showposts=5'); ?>
<?php while ($my_query->have_posts()) : $my_query->the_post(); ?>
<div id="postlist_container">
<h4 class="und"></h4>
<?php get_the_image(array( 'image_scan' => true , 'image_class' => 'small_image_left','width' => 80 , 'height' => 80)); ?><div class="post_desc"><date><?php the_time('M j, Y') ?></date> · <a href="<?php the_permalink() ?>">
<?php the_title(); ?></a> <br /><br /><?php the_excerpt_max_charlength(250); ?>
</div>
</div>
<div class="clear"></div>
<?php endwhile; ?>
<?php
function the_excerpt_max_charlength($charlength) {
$excerpt = get_the_excerpt();
$charlength++;
if ( mb_strlen( $excerpt ) > $charlength ) {
$subex = mb_substr( $excerpt, 0, $charlength - 5 );
$exwords = explode( ' ', $subex );
$excut = - ( mb_strlen( $exwords[ count( $exwords ) - 1 ] ) );
if ( $excut < 0 ) {
echo mb_substr( $subex, 0, $excut );
} else {
echo $subex;
}
echo '[...]';
} else {
echo $excerpt;
}
}
?>
</phpcode>

Answer 1

If the date/source are always the same length (which is probably unlikely), then you could use substr() on $excerpt to remove X number of characters:
// assume we want to remove the first 10 chars
$chars_to_skip = 10;
// get the full excerpt
$excerpt = get_the_excerpt();
// check the length
if ( strlen( $excerpt ) > $chars_to_skip ){
// remove chars from the beginning of the excerpt
$excerpt = substr( $excerpt, $chars_to_skip );
}
What's more likely is that you would need to do a regex search and replace to remove whatever the pattern matches even when the exact length of the source or date text differs post to post. You could use preg_replace() (api info) to accomplish this, but I can't help with the regular expression not knowing the format you're using.