php - comparing arrays in php and assign values from one to another

Question

been woking on a project of mine for a few days now, and essentialy what i'm triing to do in this project is a comparison of csv file that a user normaly does in excel, to do it in php automaticly every night. I got the info from the CSV's intro arrays, but i'm having trouble combinig them to get the right info for every book, hence the folowing exemple and question.

I have the folowing array (array1) from a csv file :

Array
(
[0] => Array
    (
        [0] => book1
        [1] => description1
        [2] => category1
        [3] => code1
        [4] => editor1
        [5] => 0
        [6] => eur
        [7] => out of stoc
    )

[1] => Array
    (
        [0] => book2
        [1] => description2
        [2] => category2
        [3] => code2
        [4] => editor2
        [5] => 0
        [6] => curr2
        [7] => out of stoc
    )

[2] => Array
    (
        [0] => book3
        [1] => description3
        [2] => category3
        [3] => code3
        [4] => editor3
        [5] => 0
        [6] => curr3
        [7] => out of stoc
    )

[3] => 
)

and another array (array2) from a second csv file :

Array
(
[0] => Array
    (
        [0] => book1
        [1] => description_from_array2
        [2] => category_from_array2
        [3] => code_from_array2
        [4] => editor_from_array2
        [5] => 12
        [6] => eur
        [7] => in stoc
    )

[1] => Array
    (
        [0] => book2
        [1] => description_from_array2
        [2] => category_from_array2
        [3] => code_from_array2
        [4] => editor_from_array2
        [5] => 13
        [6] => eur
        [7] => in stoc
    )

[2] => Array
    (
        [0] => book4
        [1] => description_from_array2
        [2] => category_from_array2
        [3] => code_from_array2
        [4] => editor_from_array2
        [5] => 14
        [6] => usd
        [7] => in stoc
    )

[3] => Array
    (
        [0] => book5
        [1] => description_from_array2
        [2] => category_from_array2
        [3] => code_from_array2
        [4] => editor_from_array2
        [5] => 16
        [6] => usd
        [7] => in stoc
    )

)

I would like to know how to get the values form array2 intro array1 for the books of array1 found in array2. Ex:

Array
(
[0] => Array
(
    [0] => book1
    [1] => description2_from_array2
    [2] => category2_from_array2
    [3] => code2_from_array2
    [4] => editor2_from_array2
    [5] => 12
    [6] => eur
    [7] => in stoc
)

[1] => Array
(
    [0] => book2
    [1] => description_from_array2
    [2] => category_from_array2
    [3] => code_from_array2
    [4] => editor_from_array2
    [5] => 13
    [6] => curr_from_array2
    [7] => in stoc
)

[2] => Array
(
    [0] => book3
    [1] => description3
    [2] => category3
    [3] => code3
    [4] => editor3
    [5] => 0
    [6] => curr3
    [7] => out of stoc //because book3 is not found in array2
)

[3] => 
)

Any help for this question would be greatly appreciated, belive me!

Answer 1

//Add keys to array 2 to aid lookup
$array2Tmp = array();
foreach($array2 as $item){
    $array2Tmp[$item[0]] = $item;
}

$array3 = array();
foreach($array1 as $item){
    //Use item from second array if it exists
    if(array_key_exists($item[0],$array2Tmp)){
       $array3[] = $array2Tmp[$item[0]];
     }else{
       $array3[] = $item;
     }
}