Check if string contains word in array

Question

This is for a chat page. I have a $string = \"This dude is a mothertrucker\". I have an array of badwords: $bads = array(\'truck\', \'shot\', etc)

Answer 1

You can flip your bad word array and do the same checking much faster. Define each bad word as a key of the array. For example,

//define global variable that is available to too part of php script
//you don't want to redefine the array each time you call the function
//as a work around you may write a class if you don't want global variable
$GLOBALS['bad_words']= array('truck' => true, 'shot' => true);

function containsBadWord($str){
    //get rid of extra white spaces at the end and beginning of the string
    $str= trim($str);
    //replace multiple white spaces next to each other with single space.
    //So we don't have problem when we use explode on the string(we dont want empty elements in the array)
    $str= preg_replace('/\s+/', ' ', $str);

    $word_list= explode(" ", $str);
    foreach($word_list as $word){
        if( isset($GLOBALS['bad_words'][$word]) ){
            return true;
        }
    }
    return false;
}

$string = "This dude is a mothertrucker";

if ( !containsBadWord($string) ){
    //doesn't contain bad word
}
else{
    //contains bad word
}

In this code we are just checking if an index exist rather than comparing bad word with all the words in the bad word list.
isset is much faster than in_array and marginally faster than array_key_exists.
Make sure none of the values in bad word array are set to null.
isset will return false if the array index is set to null.

Answer 2

Put and exit or die once it find any bad words, like this

foreach ($bads as $bad) {
 if (strpos($string,$bad) !== false) {
        //say NO!
 }
 else {
        echo YES;
        die(); or exit;            
  }
}

Answer 3

I would go that way if chat string is not that long.

$badwords = array('motherfucker', 'ass', 'hole');
$chatstr = 'This dude is a motherfucker';
$chatstrArr = explode(' ',$chatstr);
$badwordfound = false;
foreach ($chatstrArr as $k => $v) {
    if (in_array($v,$badwords)) {$badwordfound = true; break;}
    foreach($badwords as $kb => $vb) {
        if (strstr($v, $kb)) $badwordfound = true;
        break;
    }
}
if ($badwordfound) { echo 'Youre nasty!';}
else echo 'GoodGuy!';

Answer 4

 $string = "This dude is a good man";   
 $bad = array('truck','shot','etc'); 
 $flag='0';         
 foreach($bad as $word){        
    if(in_array($word,$string))        
    {       
        $flag=1;       
    }       
}       
if($flag==1)
  echo "Exist";
else
  echo "Not Exist";

Answer 5

There is a very short php script that you can use to identify bad words in a string which uses str_ireplace as follows:

$string = "This dude is a mean mothertrucker";
$badwords = array('truck', 'shot', 'ass');
$banstring = ($string != str_ireplace($badwords,"XX",$string))? true: false;
if ($banstring) {
   echo 'Bad words found';
} else {
    echo 'No bad words in the string';
}

The single line:

$banstring = ($string != str_ireplace($badwords,"XX",$string))? true: false;

does all the work.

Answer 6

can you please try this instead of your code

$string = "This dude is a mothertrucker";
$bads = array('truck', 'shot');
foreach($bads as $bad) {
    $place = strpos($string, $bad);
    if (!empty($place)) {
        echo 'Bad word';
        exit;
    } else {
        echo "Good";
    }
}