PHP compare two arrays from different locations - php

Question

I am wanting to compare two different arrays. Basically I have a database with phrases in and on my website I have a search function where the user types in a phrase.
When they click search I have a PHP page which 'explodes' the string typed in by the user and its put into an array.
Then I pull all the phrases from my database where I have also used the 'explode' function and split all the words into an array.
I now want to compare all the arrays to find close matches with 3 or more words matching each phrase.
How do I do this?
Well what I've tried totally failed, but here is what I have
$search_term = filter_var($_GET["s"], FILTER_SANITIZE_STRING); //user entered data
$search_term = str_replace ("?", "", $search_term); //removes question marks
$array = explode(" ", $search_term); //breaks apart user entered data
foreach ($array as $key=>$word) {
$array[$key] = " title LIKE '%".$word."%' "; //creates condition for MySQL query
}
$q = "SELECT * FROM posts WHERE " . implode(' OR ', $array) . " LIMIT 0,10";
$r = mysql_query($q);
while($row = mysql_fetch_assoc($r)){
$thetitle = $row['title'];
$thetitle = str_replace ("?", "", $thetitle);
$title_array[] = $thetitle;
$newarray = explode(" ", $search_term);
foreach ($newarray as $key=>$newword) {
foreach($title_array as $key => $value) {
$thenewarray = explode(" ", $value);
$contacts = array_diff_key($thenewarray, array_flip($newarray));
foreach($contacts as $key => $value) {
echo $newword."<br />";
echo $value."<br /><hr />";
}
}
}
But basically all I want is to display suggested phrases which are similar to what the user has already typed into the search box.
So If I searched "How do I compare two arrays that have the same values?", I would see 10 suggestions that are worded similar, so like "How to compare multiple arrays?" or "can I compare two arrays" etc...
So basically like when I first posted this question on this site, I got other questions that may help, thats basically what I want. This code im using was origionally to match just one word or an exact matching string, im editing it to find matching words and only show phrases with 3 or more matching words.

Answer 1

I don't think that this is the best solution for your search script. But I'll try to give you the answer:
<?php
$string1 = "This is my first string";
$string2 = "And here is my second string";
$array1 = explode(" ", $string1);
$array2 = explode(" ", $string2);
$num = 0;
foreach($array1 as $arr) {
if(in_array($arr, $array2))
$num++;
}
$match = $num >= 3 ? true : false;
?>

Answer 2

use array_intersect function
$firstArray = "This is a test only";
$secondArray = "This is test";
$array1 = explode(" ", $firstArray);
$array2 = explode(" ", $secondArray);
$result = array_intersect($array1, $array2);
$noOfWordMatch = count($result);
$check = $noOfWordMatch >= 3 ? true : false; ;