(PHP 3>= 3.0.9, PHP 4 >= 4.0b1)
preg_match -- Perform a regular expression match
Description
int preg_match (string pattern, string subject [, array
matches])
Searches subject for a match to the regular
expression given in pattern.
If matches is provided, then it is filled
with the results of search. $matches[0] will contain the text that
match the full pattern, $matches[1] will have the text that matched
the first captured parenthesized subpattern, and so on.
Returns TRUE if a match for pattern was
found in the subject string, or FALSE if not match was found
or an error occurred.
Example 1. Find the string of text "php"
// the "i" after the pattern delimiter indicates a case-insensitive search
if (preg_match ("/php/i", "PHP is the web scripting language of choice.")) {
print "A match was found.";
} else {
print "A match was not found.";
}
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Example 2. find the word "web"
// the \b in the pattern indicates a word boundary, so only the distinct
// word "web" is matched, and not a word partial like "webbing" or "cobweb"
if (preg_match ("/\bweb\b/i", "PHP is the web scripting language of choice.")) {
print "A match was found.";
} else {
print "A match was not found.";
}
if (preg_match ("/\bweb\b/i", "PHP is the website scripting language of choice.")) {
print "A match was found.";
} else {
print "A match was not found.";
}
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Example 3. Getting the domain name out of a URL
// get host name from URL
preg_match("/^(http:\/\/)?([^\/]+)/i",
"http://www.php.net/index.html", $matches);
$host = $matches[2];
// get last two segments of host name
preg_match("/[^\.\/]+\.[^\.\/]+$/",$host,$matches);
echo "domain name is: ".$matches[0]."\n";
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This example will produce:
See also
preg_match_all(),
preg_replace(), and
preg_split().