PHP Array compare using loops

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.

Which raises the question, why do you want to use loops rather than the built-in functions? — Mark Baker
– Mark Baker, Commented Dec 6, 2012 at 11:09
This is absolutely ridiculous, once you compare the arrays you will need to do the for loops all over again to compare the other array. Stop fighting the inbuilt functions — Dale
– Dale, Commented Dec 6, 2012 at 11:33

Dale · Accepted Answer · 2012-12-06 11:25:25Z

2

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.

edited Dec 6, 2012 at 11:25

answered Dec 6, 2012 at 10:58

Dale

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3 Comments

Andrea Casaccia Over a year ago

I guess in_array() is not allowed

Mayank K. Swami Over a year ago

@Dale ahh...please use one more loop ...instead in_array() ...:P

Dale Over a year ago

@NullPointer I have my reasons for quitting :)

dognose · Accepted Answer · 2012-12-06 11:00:49Z

1

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 )

answered Dec 6, 2012 at 11:00

dognose

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Comments

Andrea Casaccia · Accepted Answer · 2012-12-06 11:14:23Z

1

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.

edited Dec 6, 2012 at 11:14

answered Dec 6, 2012 at 11:04

Andrea Casaccia

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Comments

Peter · Accepted Answer · 2012-12-06 13:19:56Z

1

    <?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.

edited Dec 6, 2012 at 13:19

Peter

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answered Dec 6, 2012 at 12:59

vaibhav

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