how to filter porn article?

$article="there are some of porn keywords, porn is not allowed print";

if($aticle without "porn")
{
echo "nothing";
}
else
{
echo "$article";
}
above that is my wish, but it's incorrect php syntax.
could you teach me correct php syntax?

thank you

 

<?php

$article = "there are some of porn keywords, porn is not allowed print";

if(!preg_match('~\bporn\b~i', $article))
{
//Article does not contain the word porn...
}
else
{
//Article contains the word porn...
}

?>

PHP:

 

Heres an example, to work with more than one word.

<?php

$article = "there are some of porn keywords, porn is not allowed print";

//array of words to disallow
$words_to_disallow = array('porn', 'sex');

$escaped = array_map('preg_quote', $words_to_disallow);

if(!preg_match('~\b('.implode("|", $escaped).')\b~i', $article))
{
echo "Article seems clean...";
}
else
{
echo "Article contains a disallowed word...";
}

?>

PHP:

 

it's works.
Thank you so much.