PHP check if two keywords occur in String - php

Question

my challange explained on the following example: The keyword combination "gaming notebook" is given.
I want to check whether the two keywords occur in a string. The challange is that the string could look like this:
"Nice Gaming Notebook"
"Notebook for Gaming"
"Notebook for extreme Gaming"
I want my function to return true for all of the three strings. There is a tolerance of 3-4 words that can be between the word combination and as the examples show, I want it to work if the keywords are switched.
So my approach was the following, but it does not seem to work:
$keyword = strtolower("gaming notebook");
$parts = explode(" ", $keyword);
$string = strtolower("Which notebook for good gaming performance");
//point to end of the array
end($parts);
//fetch key of the last element of the array.
$lastElementKey = key($parts);
//iterate the array
$searchExpression = "";
foreach($parts as $k => $v) {
if($k != $lastElementKey) {
$searchExpression .= $v . "|";
} else {
$searchExpression .= $v;
}
}
if(preg_match_all('#\b('. $searchExpression .')\b#', $string, $matches) > 0) {
echo "Jep, keyword combination is in string";
} else {
echo "No, keyword combination is not in string";
}

Answer 1

You want to use something like CMU Sphinx or a natural language index in your database. (See http://dev.mysql.com/doc/refman/5.7/en/fulltext-natural-language.html) Doing a quick search of php libraries turned up "nlp-tools/nlp-tools," however, I have never used a pure php solution to accomplish what you are trying to do.

Answer 2

The solution using preg_match_all and array_intersect functions:
$keywordStr = "gaming notebook";
$string = "Which notebook for good gaming performance,it's my notebook";
$keywords = explode(" ", $keywordStr);
$parts = implode("|", $keywords);
preg_match_all("/\b$parts\b/i", $string, $matches);
// matched items should contain all needed keywords
if (count($keywords) == count(array_intersect($keywords, $matches[0]))) {
echo "Jep, keyword combination is in string";
} else {
echo "No, keyword combination is not in string";
}

Answer 3

<?php
$keyword = strtolower("gaming notebook");
$string = strtolower("Which notebooks for good gaming performance");
function check($keyword,$string){
$parts = explode(' ',$keyword);
$result = false;
$pattern = implode('|',$parts);
preg_match_all("(\b{$pattern}\b)",$string,$matches);
if(isset($matches[0])){
return true;
}
return false;
}
var_dump(check($keyword, $string));

Answer 4

$reg = "/(?:\b$kw1(?:\s+\w+){0,4}\s+$kw2\b)|(?:\b$kw2(?:\s+\w+){0,4}\s+$kw1\b)/";
if (preg_match($reg, $string)) {
echo "OK\n";
} else {
echo "KO\n";
}
This will echo OK when the 2 keywords occur in the string, in any order and separated by at most 4 words.
Explanation:
/
(?: : non capture group
\b$kw1 : keyword 1
(?:\s+\w+){0,4} : followed by 0 to 4 other word
\s+ : space(s)
$kw2\b : keyword 2
)
|
(?: : non capture group
\b$kw2 : keyword 2
(?:\s+\w+){0,4} : followed by 0 to 4 other word
\s+ : space(s)
$kw1\b : keyword 1
)
/