function trim_text_in_sentences($intLength, $strText) {
    $intLastPeriodPos = strpos(strrev(substr($strText, 0, $intLength)), '.');
    if ($intLastPeriodPos === false) {
        $strReturn = substr($strText, 0, $intLength);
    } else {
        $strReturn = substr($strText, 0, ($intLength - $intLastPeriodPos));
    }
    return $strReturn;
}

function trim_text_in_sentences($intLength, $strText) {
    $intLastPeriodPos = strpos(strrev(substr($strText, 0, 200)), '.');
    if ($intLastPeriodPos === false) {
        $strReturn = substr($strText, 0, 200);
    } else {
        $strReturn = substr($strText, 0, (200 - $intLastPeriodPos));
    }
    return $strReturn;
}

http://www.addedbytes.com/code/

Pass in text and the maximum allowable length and this snippet will return as many full sentences from the text as it can within that length. If no sentences, it will just trim to the maximum length allowed.

PHP Get First Characters of String in Complete Sentences

php

PHP