Remove portion of a string after a certain charact

Question

I'm just wondering how I could remove everything after a certain substring in PHP

ex:

Posted On April 6th By Some Dude

I'd like to have it so that it removes all the text including, and after, the sub string "By"

Thanks

Answer 1

Below is the most efficient method (by run-time) to cut off everything after the first By in a string. If By does not exist, the full string is returned. The result is in $sResult.

$sInputString = "Posted On April 6th By Some Dude";
$sControl = "By";

//Get Position Of 'By'
$iPosition = strpos($sInputString, " ".$sControl);
if ($iPosition !== false)
  //Cut Off If String Exists
  $sResult = substr($sInputString, 0, $iPosition);
else
  //Deal With String Not Found
  $sResult = $sInputString;

//$sResult = "Posted On April 6th"

If you don't want to be case sensitive, use stripos instead of strpos. If you think By might exist more than once and want to cut everything after the last occurrence, use strrpos.

Below is a less efficient method but it takes up less code space. This method is also more flexible and allows you to do any regular expression.

$sInputString = "Posted On April 6th By Some Dude";
$pControl = "By";

$sResult = preg_replace("' ".$pControl.".*'s", '', $sInputString);

//$sResult = "Posted On April 6th"

For example, if you wanted to remove everything after the day:

$sInputString = "Posted On April 6th By Some Dude";
$pControl = "[0-9]{1,2}[a-z]{2}"; //1 or 2 numbers followed by 2 lowercase letters.

$sResult = preg_replace("' ".$pControl.".*'s", '', $sInputString);

//$sResult = "Posted On April"

For case insensitive, add the i modifier like this:

$sResult = preg_replace("' ".$pControl.".*'si", '', $sInputString);

To get everything past the last By if you think there might be more than one, add an extra .* at the beginning like this:

$sResult = preg_replace("'.* ".$pControl.".*'si", '', $sInputString);

But here is also a really powerful way you can use preg_match to do what you may be trying to do:

$sInputString = "Posted On April 6th By Some Dude";

$pPattern = "'Posted On (.*?) By (.*?)'s";
if (preg_match($pPattern, $sInputString, $aMatch)) {
  //Deal With Match
  //$aMatch[1] = "April 6th"
  //$aMatch[2] = "Some Dude"
} else {
  //No Match Found
}

Regular expressions might seem confusing at first but they can be really powerful and your best friend once you master them! Good luck!

Answer 2

One method would be:

$str = 'Posted On April 6th By Some Dude';
echo strtok($str, 'By'); // Posted On April 6th

Answer 3

$var = "Posted On April 6th By Some Dude";
$new_var = substr($var, 0, strpos($var, " By"));