PHP regex with preg_replace and the "." character - php

Question

I have scientific names in the following format:
S. daemon
A. cacatuoides
B. splendens
Etc, etc.
I'm having difficulty with the "." character.
This code works for full species names (i.e. Satanoperca daemon):
foreach ($species as $term) {
$term_norm = preg_replace('/\s+/', ' ', strtoupper(trim($term)));
$pattern[] = preg_replace('/ /', '\\s+', preg_quote($term_norm));
$urls[$term_norm] = '/dev/species/' . str_replace(" ", "-", rawurlencode($term));
$rels[$term_norm] = $urls[$term_norm] . '?preview=true';
$title[$term_norm] = $term;
But I can't get it to work for the aforementioned examples:
$genus_species = explode(" ", $term);
$genus = $genus_species[0];
$species = $genus_species[1];
$initial = substr($genus, 0, 1);
$shortened = $initial . '. ' . $species;
$term_norm = preg_replace('/\s+/', ' ', strtoupper(trim($shortened)));
$pattern[] = preg_replace('/ /', '\\s+', preg_quote($term_norm));
$urls[$term_norm] = '/dev/species/' . rawurlencode($term);
$rels[$term_norm] = $urls[$term_norm] . '?preview=true';
$title[$term_norm] = $term;
If I use this code, nearly all of my source, i.e. every word/character, is linked with . If I comment the code out, the full name linking works perfectly and not such problem occurs.
A little more info...
$pattern is echoing out as: /\b(SATANOPERCA\s+DAEMON|S(\.)\s+DAEMON)\b/i
The input is a list of species names, such as the ones I previously mentioned. The source is a species profile, which often refers to other species.
What I'd like the code to do is replace any mention of these species names with a link to that species profile.
Thanks in advance,

Answer 1

While looking into your issue I ran over the way you initially build the regular expression. I thought, why not simplify it? Here is what I've come up with:
foreach ($terms as $term) {
list($genus, $species) = explode(' ', $term);
$pattern = sprintf('~\b((?:%s[.]|%s) %s)~i', $genus[0], $genus, $species);
Which gives the following
~\b((?:S[.]|Satanoperca) daemon)~i
I'm making use of list here in combination with explode which often is less code, so better readable.
To build the regular expression I use sprintf which often is easier to formulate complex strings you need substitution in. It allows the usage of a mask.
Finally $genus[0] is the first character of $genus. You might need to replace it in case you're using a multibyte character set. Just saying.
The pattern itself is streamlined as well:
~\b((?:S[.]|Satanoperca) daemon)~i
The first subgroup is non-catching (?:) and offers both variants: Short with . or the long genus. Then followed by the space and finally the species. I also use [.] to express the dot in there, but sure \. would work as well:
~\b((?:S\.|Satanoperca) daemon)~i
What's left is the replacement procedure. I opted for using a callback function here. As the link needs only be build once for the term, I add that on top of the foreach. Again I'm using sprintf to format it:
foreach ($terms as $term) {
$termSlug = strtolower(strtr($term, array(' ' => '-')));
$termHref = sprintf('/dev/species/%s', rawurlencode($termSlug));
list($genus, $species) = explode(' ', $term);
$pattern = sprintf('~\b((?:%s\.|%s) %s)~i', $genus[0], $genus, $species);
What's left is the callback function that replaces every match with the link:
$string = preg_replace_callback($pattern, function($match) use($term, $termHref)
{
return sprintf('%s', $termHref
, htmlspecialchars($term), htmlspecialchars($match[1]));
}, $string);
And that's it. The full example:
$string = <<<STR
S. daemon
Satanoperca daemon
A. cacatuoides
B. splendens
STR;
$terms = array(
'Satanoperca daemon',
);
foreach ($terms as $term) {
$termSlug = strtolower(strtr($term, array(' ' => '-')));
$termHref = sprintf('/dev/species/%s', rawurlencode($termSlug));
list($genus, $species) = explode(' ', $term);
$pattern = sprintf('~\b((?:%s\.|%s) %s)~i', $genus[0], $genus, $species);
echo $pattern, "\n";
$string = preg_replace_callback($pattern, function($match) use($term, $termHref)
{
return sprintf('%s', $termHref
, htmlspecialchars($term), htmlspecialchars($match[1]));
}, $string);
}
echo $string;
And it's output:
S. daemon
Satanoperca daemon
A. cacatuoides
B. splendens
I hope this is helpful even it's completely new code everywhere.
Validate Terms:
// validate terms
$valid = '/^\w+ \w+$/';
foreach ($terms as $index => $term) {
if ($result = preg_match($valid, $term))
continue;
printf("Invalid Term: (%d) %s\n", $index, $term);
}

Answer 2

Do you want to include the . also like this
$term_norm = preg_replace('/[\s\.]+/', ' ', strtoupper(trim($shortened)));