Title Case Function in PHP Based on Grammatical Rules for Capitalizing the Words in a Title
Last Updated on Wednesday, 06 January 2010 01:18
Written by Nicholas Dunbar
Creating a Title Case Function with PHP Based on Grammatical Rules.
There are many different articles on the web about using PHP to title case a string. Most don't try to encompass the more complicated grammatical rules that govern title case. There are 2 major standard ways that title case is done. I have written a function that follows all the grammatical rules of "Headline Case" If you have titles where you would have exceptions to these rules, I have provided the tags <no_parse> as a feature of the function below. In the case were you want to take over formatting and override the parser you can uses these tags to exempt it from the title casing parser. This way 90% of all situations are covered after which you only have to manually tweak a few entries. This takes so much of the grunt work out of data entry. In any case the tags are provided for your convenience. You may notice that the New York Times is inconsitant on which style rules they use for title case. If they used an algorithm like mine there would be automatic standardization.
<?
//
//Converts a string to Title Case based on one set of title case rules
// put <no_parse></no_parse> around content that you don't want to be parsed by the title case rules
//
function titleCase($string) {
//remove no_parse content
$string_array = preg_split("/(<no_parse>|<\/no_parse>)+/i",$string);
$newString = "";
for ($k=0; $k<count($string_array); $k=$k+2){
$string = $string_array[$k];
//if the entire string is upper case dont perform any title case on it
if ($string != strtoupper($string)){
//TITLE CASE RULES:
//1.) uppercase the first char in every word
$new = preg_replace("/(^|\s|\'|'|\"|-){1}([a-z]){1}/ie","''.stripslashes('\\1').''.stripslashes(strtoupper('\\2')).''", $string);
//2.) lower case words exempt from title case
// Lowercase all articles, coordinate conjunctions ("and", "or", "nor"), and prepositions regardless of length, when they are other than the first or last word.
// Lowercase the "to" in an infinitive." - this rule is of course aproximated since it is contex sensitive
$matches = array();
// perform recusive matching on the following words
preg_match_all("/(\sof|\sa|\san|\sthe|\sbut|\sor|\snot|\syet|\sat|\son|\sin|\sover|\sabove|\sunder|\sbelow|\sbehind|\snext\sto|\sbeside|\sby|\samoung|\sbetween|\sby|\still|\ssince|\sdurring|\sfor|\sthroughout|\sto|\sand){2}/i",$new ,$matches);
for ($i=0; $i<count($matches); $i++){
for ($j=0; $j<count($matches[$i]); $j++){
$new = preg_replace("/(".$matches[$i][$j]."\s)/ise","''.strtolower('\\1').''",$new);
}
}
//3.) do not allow upper case appostraphies
$new = preg_replace("/(\w'S)/ie","''.strtolower('\\1').''",$new);
$new = preg_replace("/(\w'\w)/ie","''.strtolower('\\1').''",$new);
$new = preg_replace("/(\W)(of|a|an|the|but|or|not|yet|at|on|in|over|above|under|below|behind|next to| beside|by|amoung|between|by|till|since|durring|for|throughout|to|and)(\W)/ise","'\\1'.strtolower('\\2').'\\3'",$new);
//4.) capitalize first letter in the string always
$new = preg_replace("/(^[a-z]){1}/ie","''.strtoupper('\\1').''", $new);
//5.) replace special cases
// you will add to this as you find case specific problems
$new = preg_replace("/\sin-/i"," In-",$new);
$new = preg_replace("/(\s|\"|\'){1}(ph){1}(\s|,|\.|\"|\'|:|!|\?|\*|$){1}/ie","'\\1pH\\3'",$new);
$new = preg_replace("/^ph(\s|$)/i","pH ",$new);
$new = preg_replace("/(\s)ph($)/i"," pH",$new);
$new = preg_replace("/(\s|\"|\'){1}(&){1}(\s|,|\.|\"|\'|:|!|\?|\*){1}/ie","'\\1and\\3'",$new);
$new = preg_replace("/(\s|\"|\'){1}(groundwater){1}(\s|,|\.|\"|\'|:|!|\?|\*){1}/e","'\\1Ground Water\\3'",$new);
$new = preg_replace("/(\W|^){1}(cross){1}(\s){1}(connection){1}(\W|$){1}/ie","'\\1\\2-\\4\\5'",$new); //always hyphonate cross-connections
$new = preg_replace("/(\s|\"|\'){1}(vs\.){1}(\s|,|\.|\"|\'|:|!|\?|\*){1}/ie","'\\1Vs.\\3'",$new);
$new = preg_replace("/(\s|\"|\'){1}(on-off){1}(\s|,|\.|\"|\'|:|!|\?|\*){1}/ie","'\\1On-Off\\3'",$new);
$new = preg_replace("/(\s|\"|\'){1}(on-site){1}(\s|,|\.|\"|\'|:|!|\?|\*){1}/ie","'\\1On-Site\\3'",$new);
// special cases like Class A Fires
$new = preg_replace("/(\s|\"|\'){1}(class\s){1}(\w){1}(\s|,|\.|\"|\'|:|!|\?|\*|$){1}/ie","'\\1\\2'.strtoupper('\\3').'\\4'",$new);
$new = stripslashes($new);
$string_array[$k] = $new;
}
}
for ($k=0; $k<count($string_array); $k++){
$newString .= $string_array[$k];
}
return($newString);
};
// test the function
echo titleCase("this is a test <no_parse>do you not believe me</no_parse> here is the rest of the string");
// out put : This Is A Test do you not believe me Here Is The Rest of The String
?>
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