Question

I’m writing a trimming function that takes a string and finds the first newline \n character after the 500th character and returns a string up to the newline. Basically, if there are \n at indices of 200, 400, and 600, I want the function to return the first 600 characters of the string (not including the \n).

I tried:

$output = preg_replace('/([^%]{500}[^\n]+?)[^%]*/','$1',$output);

I used the percent sign because I couldn’t find a character class that just encompassed “everthing”. Dot didn’t do it because it excluded newlines. Unfortunately, my function fails miserably. Any help or guidance would be appreciated.

Answer 1

Personally I would avoid regex and use simple string functions:

// $str is the original string
$nl = strpos( $str, "\n", 500 ); // finds first \n starting from char 500
$sub = substr( $str, 0, $nl );
$final = str_replace( "\n", ' ', $sub );

You might need to check for \r\n as well – i.e. normalize first using str_replace( "\r\n", "\n", $str ).