Question

function highlight_phrase($str, $phrase, $class='highlight') 
{ 
     if ($str == '') 
     { 
         return ''; 
     } 

     if ($phrase != '') 
     { 
         return preg_replace('/('.preg_quote($phrase, '/').')/Ui', '<span class="'.$class.'">'."\\1".'</span>', $str); 
     }  
     return $str; 
} 

above code is what i use to highlight phrases in a string. I have problem with following issues:

1. if phrase is new car it matches new car and new cars both in a string meaning it highlights new car of new cars but i need not highlight new cars.

2. I could check for space but what if phrase ends with ,.? or ! etc.

Answer 1

Use the \b pattern to match word boundaries, i.e. in your case /\b(new car)\b/ will match

• “the new car is blue”
• “the new car.”
• “new car“

but not

• “all the new cars”.