How to split a string by multiple delimiters in PHP?

Try:

$arr=preg_split("/s+(?=S*+$)/",$str);

Edit

A short explanation:

The (?= ... ) is called a positive look ahead. For example, a(?=b) will only match a single 'a' if the next character (the one to the right of it) is a 'b'. Note that the 'b' is not a part of the match!

The S is just a short-hand for the character class [^s]. In other words: it matches a single character other than a white space character. The + after the * makes the character class S possessive.

Finally, the $ denotes the end of the string.

To recap, the complete regex s+(?=S*+$) would read in plain English as follows:

match one or more white space characters only when looking ahead of those white space characters zero or more characters other than white space characters, followed by the end of the string, can be seen.

correct me if i'm wrong, but i don't think you can do this with a simple regexp. in a full regexp implementation you could use something like this :

$parts = preg_split("/(?<!<[^>]*)./", $input);

but php does not allow non-fixed-length lookbehind, so that won't work. apparently the only 2 that do are jgsoft and the .net regexp. Useful Page

my method of dealing with this would be :

function splitStringUp($input, $maxlen) {
    $parts = explode(".", $input);
    $i = 0;
    while ($i < count($parts)) {
        if (preg_match("/<[^>]*$/", $parts[$i])) {
            array_splice($parts, $i, 2, $parts[$i] . "." . $parts[$i+1]);
        } else {
            if ($i < (count($parts) - 1) && strlen($parts[$i] . "." . $parts[$i+1]) < $maxlen) {
                array_splice($parts, $i, 2, $parts[$i] . "." . $parts[$i+1]);
            } else {
                $i++;
            }
        }
    }
    return $parts;
}

you didn't mention what you want to happen when an individual sentence is >8000 chars long, so this just leaves them intact.

sample output :

splitStringUp("this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag. and the closing tag</a>. hooray", 8000);
array(1) {
  [0]=> string(114) "this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag. and the closing tag</a>. hooray"
}

splitStringUp("this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag. and the closing tag</a>. hooray", 80);
array(2) {
  [0]=> string(81) "this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag"
  [1]=> string(32) " and the closing tag</a>. hooray"
}

splitStringUp("this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag. and the closing tag</a>. hooray", 40);
array(4) {
  [0]=> string(18) "this is a sentence"
  [1]=> string(25) " this is another sentence"
  [2]=> string(36) " this is an html <a href="a.b.c">tag"
  [3]=> string(32) " and the closing tag</a>. hooray"
}

splitStringUp("this is a sentence. this is another sentence. this is an html <a href="a.b.c">tag. and the closing tag</a>. hooray", 0);
array(5) {
  [0]=> string(18) "this is a sentence"
  [1]=> string(25) " this is another sentence"
  [2]=> string(36) " this is an html <a href="a.b.c">tag"
  [3]=> string(24) " and the closing tag</a>"
  [4]=> string(7) " hooray"
}