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I have two arrays of arrays containing a country name and a corresponding analytical metric. I need to subtract them (based on the first sub array value, i.e. the country) to return a third array of the countries found only in the first and not in the second. Example input and output:

First Array:

Array
(
    [0] => Array
        (
            [0] => Afghanistan
            [1] => 1
        )

    [1] => Array
        (
            [0] => Albania
            [1] => 1
        )
)

Second Array:

Array
(
    [0] => Array // not found in 1st array by country name
        (
            [0] => Australia
            [1] => 2
        )

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

Intended Output

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

array_dif(); is returning no differences, despite there being many in my data sets. How can I go about creating this subtracted third array (in PHP)?

share|improve this question

1 Answer 1

up vote 0 down vote accepted

Try this

$array1=array('0'=>Array('0' => 'Afghanistan','1' => '1'),
        '1'=>Array('0' => 'Albania','1' => '1')     );
$array2 = Array('0' => Array ('0' => 'Australia','1' => '2'),
    '1' => Array('0' => 'Albania','1' => '2'));
$finalArray = diffArray($array1,$array2); //returns your expected result


function diffArray($array1,$array2){    
    $newarray = array();
    foreach ($array2 as $tmp){
        $duplicate = false;
        foreach($array1 as $tmp1){
            if ($tmp[0] == $tmp1[0]){
                $duplicate=true;
            } 
        }
        if(!$duplicate)
        $newarray[] = $tmp;
    }
    return $newarray;
}
share|improve this answer
    
Worked a treat - thank you! –  Ryan Brodie Jul 31 '12 at 8:29

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