PHP: the problem of merging arrays

Question

OK I have this function (I got the answer to this question ), which combines the array as follows:

Functions

function readArray( $arr, $k, $default = 0 ) {
    return isset( $arr[$k] ) ? $arr[$k] : $default ;
}

function merge( $arr1, $arr2 ) {
    $result = array() ;
    foreach( $arr1 as $k => $v ) {
        if( is_numeric( $v ) ) {
            $result[$k] = (int)$v + (int) readArray( $arr2, $k ) ;
        } else {
            $result[$k] = merge( $v, readArray($arr2, $k, array()) ) ;
        }
    }
    return $result ;
}

Using

$basketA = array( "fruit" => array(), "drink" => array() ) ;
$basketA['fruit']['apple'] = 1;
$basketA['fruit']['orange'] = 2;
$basketA['fruit']['banana'] = 3;
$basketA['drink']['soda'] = 4;
$basketA['drink']['milk'] = 5;

$basketB = array( "fruit" => array(), "drink" => array() ) ;
$basketB['fruit']['apple'] = 2;
$basketB['fruit']['orange'] = 2;
$basketB['fruit']['banana'] = 2;
$basketB['drink']['soda'] = 2;
$basketB['drink']['milk'] = 2;

$basketC = merge( $basketA, $basketB ) ;
print_r( $basketC ) ;

Output

Array
(
    [fruit] => Array
        (
            [apple] => 3
            [orange] => 4
            [banana] => 5
        )

    [drink] => Array
        (
            [soda] => 6
            [milk] => 7
        )

)

OK, this works with 1 flaw, I can’t figure out how to fix it: if $ arr1 is missing something that $ arr2 has, it should just use the value from $ arr2, but omit it all together instead:

Example

$basketA = array( "fruit" => array(), "drink" => array() ) ;
$basketA['fruit']['apple'] = 1;
$basketA['fruit']['orange'] = 2;
$basketA['fruit']['banana'] = 3;
$basketA['drink']['milk'] = 5;

$basketB = array( "fruit" => array(), "drink" => array() ) ;
$basketB['fruit']['apple'] = 2;
$basketB['fruit']['orange'] = 2;
$basketB['fruit']['banana'] = 2;
$basketB['drink']['soda'] = 2;
$basketB['drink']['milk'] = 2;

$basketC = merge( $basketA, $basketB ) ;
print_r( $basketC ) ;

Output

Array
(
    [fruit] => Array
        (
            [apple] => 3
            [orange] => 4
            [banana] => 5
        )

    [drink] => Array
        (
            [milk] => 7
        )

)

Note that [soda] is not in the new array, because the first array did not have this.

How can i fix this?

Thank!!!

Answer 1

Quick fix, change the function merge()like this:

function merge( $arr1, $arr2 ) {
    $result = array() ;
    foreach( $arr1 as $k => $v ) {
        if( is_numeric( $v ) ) {
            $result[$k] = (int)$v + (int) readArray( $arr2, $k ) ;
        } else {
            $result[$k] = merge( $v, readArray($arr2, $k, array()) ) ;
        }
    }
    foreach( $arr2 as $k => $v ) {
        if( is_numeric( $v ) ) {
            $result[$k] = (int)$v + (int) readArray( $arr1, $k ) ;
        } else {
            $result[$k] = merge( $v, readArray($arr1, $k, array()) ) ;
        }
    }
    return $result ;
}

Output:

Array
(
    [fruit] => Array
        (
            [apple] => 3
            [orange] => 4
            [banana] => 5
        )

    [drink] => Array
        (
            [soda] => 2
            [milk] => 7
        )
)

---

, array_merge_recursive() :

$basketC = array_merge_recursive($basketA, $basketB);

:

Array
(
    [fruit] => Array
        (
            [apple] => Array
                (
                    [0] => 1
                    [1] => 2
                )

            [orange] => Array
                (
                    [0] => 2
                    [1] => 2
                )

            [banana] => Array
                (
                    [0] => 3
                    [1] => 2
                )

        )

    [drink] => Array
        (
            [milk] => Array
                (
                    [0] => 5
                    [1] => 2
                )

            [soda] => 2
        )
)

, , $basketC, :

array_sum($basketC['fruit']['orange']); // 4

, - , .