Comparing 2 arrays

condoug

Hi all

I have 2 arrays that need to be compared and the number of matched values is what i need to retrieve.

array 1 might look like this:

Array
(
    [0] => 'A'
    [1] => 'B'
    [2] => 'C'
    [3] => 'D'
    [4] => 'E'
    [5] => 'F'
)

and array 2 might look like this:

Array
(
    [0] => 'A'
    [1] => 'A'
    [2] => 'C'
    [3] => 'D'
)

What is the best/quickest way to compare the key/values of each array and then return the number of matches? (Where in my example above I would expect the number of matches returned to be 3)

If someone could provide an example of this it would be even more helpful but I am happy to look it up with some guidance.

regards
Doug

condoug

can I just add, it is the keys that need to be compared, so the value of the first array[0] key needs to be matched ONLY to the value of the second array[0] key and so on through the array. There is no guarantee that the second array will be same length as the first array but the second array will never be larger than the first array.

Hope that makes things clearer!

laserlight

You can use [man]array_intersect/man with [man]count/man.

EDIT:
Oh wait,

can I just add, it is the keys that need to be compared, so the value of the first array[0] key needs to be matched ONLY to the value of the second array[0] key and so on through the array.

In that case a loop would be the easiest, I think.

condoug

Would you be kind enough to provide an example of looping and matching the values from the equivalent keys[] whilst producing a count?

laserlight

It could be something like this:

$count = 0;
for ($i = 0; $i < count($array1) && $i < count($array2); ++$i) {
    if ($array1[$i] == $array2[$i]) {
        ++$count;
    }
}