PHP Array compare using loops - php

Question

I am using this piece of code to compare two php arrays, I got all matched items rightly but unfortunately i am not succeeding in getting non matched items. Here is my code.
<?php
$filter1 = "blueberries,abc,cornstarch,sugar";
$cval = strtoupper($filter1);
$parts1 = explode(',',$cval);
$filter2 = "water,blueberries,sugar,cornstarch";
$values = strtoupper($filter2);
$parts2 = explode(',', $values);
$m=0;
$nm=0;
for($i = 0; $i< count($parts1); $i++)
{
for($j = 0; $j< count($parts2); $j++)
{
if($parts1[$i] == $parts2[$j])
{
$m++;
$p[] = $parts1[$i];
}
else{
$nm++;
$q[] = $parts1[$i];
}
}
}
echo $m;
echo "<br />";
echo $nm;
echo "<br />";
print_r($p);
echo "<br />";
print_r($q);
?>
Can someone help me sorting out this problem, As i dont want to use builtin array comparison functions.

Answer 1

I would use the internal functions for this (if I understood your question)
Matched:
$matched = array_intersect($parts1, $parts2);
Difference:
$difference = array_diff($parts1, $parts2);
Or in your world of for loops:
<?php
$filter1 = "blueberries,abc,cornstarch,sugar";
$cval = strtoupper($filter1);
$parts1 = explode(',', $cval);
$filter2 = "water,blueberries,sugar,cornstarch";
$values = strtoupper($filter2);
$parts2 = explode(',', $values);
$matched = $not_matched = array();
for ($i = 0; $i < count($parts1); $i++)
{
if (in_array($parts1[$i], $parts2))
{
$matched[] = $parts1[$i];
}
else
{
$not_matched[] = $parts1[$i];
}
}
print_r($matched);
print_r($not_matched);
?>
I have been working on adding another loop instead of using in_array() but I'm not going to update my answer for two reasons.
1) Use
$matched = array_intersect($parts1, $parts2);
$difference = array_diff($parts1, $parts2);
Writing this much code instead of two lines is against my religion.
2) The only reason to create this amount of code stricly not using array_* or in_array functions must be for some quiz or test, which I want to enter and win.

Answer 2

Use array_intersect, array_diff and array_merge
$filter1 = "blueberries,abc,cornstarch,sugar";
$cval = strtoupper($filter1);
$parts1 = explode(',',$cval);
$filter2 = "water,blueberries,sugar,cornstarch";
$values = strtoupper($filter2);
$parts2 = explode(',', $values);
print_r(array_intersect($parts1, $parts2));
print_r(array_merge(array_diff($parts1, $parts2), array_diff($parts2, $parts1)));
Array ( [0] => BLUEBERRIES [2] => CORNSTARCH [3] => SUGAR ) Array ( [0] => ABC [1] => WATER )

Answer 3

You are doing the cartesian product of the two arrays.
If you find that $parts1[$i] == $parts2[$j], it is correct to add $parts1[$i] to $p, but the opposite assumption (if they are different then add to $q) is wrong.
You should start with all elements in $q and when you have a match, add it to $p and remove it from $q.

Answer 4

<?php
$array1 = array("a" => "green", "red", "blue", "red");
$array2 = array("b" => "green", "yellow", "red");
$result = array_diff($array1, $array2);
print_r($result);
?>
This is the php library function.