regex/preg_replace to replace subdomain [closed]

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i need to use preg_replace to replace two subdomain elements with a single element. my regex skills are virtually nonexistent. the urls are of the form:

user1.common.domain.org
user2.common.domain.org
something.common.domain.org
else.common.domain.org

and need to be replaced with:

newvalue.domain.org

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preg_replace( '/[a-z0-9]+\.common/i' , 'newvalue' , $url );

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Try this:

preg_replace("/.+?(domain.+?)/", "newvalue.$1", "user1.common.domain.org");

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This problem might not be best-solved with a regular expression. Try using explode():

$exploded = explode('.', $hostname);
if( (count($exploded) == 4) and ($exploded[1] == 'common') )
{
    $exploded[0] = 'newvalue';
    unset($exploded[1]);
}

$hostname = implode('.', $exploded);

(where $hostname is the hostname you are checking [e.g., $_SERVER['HTTP_HOST'])

The above code assumes that you are looking for hostnames that match the pattern *.common.domain.org, and that the hostname will always end with domain.org.

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This will work:

$sd = "user1.common.domain.org";

$sd = preg_replace('/.*?\.common\.(domain\.org)/i', 'newvalue.$1', $sd);

echo $sd ;

outputs newvalue.domain.org

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try this code:

preg_replace('/\w+\.\w+(?=\.\w+\.\w+)/i', 'newvalue', 'user1.common.domain.org');

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This would be more concise:

For host:

$newValue = 'newvalue';
$newHost = preg_replace("/^.+(?:\.common)(\.domain\.org)$/", "$newValue$1", $host);

replaces string staring with any character one or more times + ".common" + ".domain" to "newvalue.domain.org"

For url:

$newValue = 'newvalue';
$newUrl = preg_replace("/^(https?:\/\/).+(?:\.common)(\.domain\.org)$/", "$1$newValue$2", $url);

replaces string staring with "http://" or "https://" + any character one or more times + ".common" + ".domain" to "http://" or "https://" + "newvalue.domain.org"

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This is only for if you can be sure it ends with domain.org:

preg_replace('/(?:.*?)\.(?:.*?)(\.domain\.org)/', $new_val."$1", $url);