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I have the following code and am trying to compare two array's with array_diff however I keep getting no results. I not sure if it matters, but there are many fields in the array and I really only want to compare 1 field...is this possible? what am I missing?

<?php
$json = file_get_contents("http://ebird.org/ws1.1/data/obs/region/recent?rtype=subnational1&r=US-AZ&back=7&fmt=json");
$json2 = file_get_contents("http://ebird.org/ws1.1/data/obs/region/recent?rtype=subnational1&r=US-NV&back=7&fmt=json");

$array1 = json_decode($json, TRUE);
$array2 = json_decode($json2, TRUE);

if ( $array1 == $array2 ) {
echo 'There are no differences';
}else 
var_dump(array_diff($array2, $array1));
echo 'they are different';

?>
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Did you read the manual on equality comparison for arrays and on array_diff? –  Jon Apr 9 at 17:32
 
Why not compare the JSON as a string. If they are equal then the array/object is going to be the same when they are decoded anyhow. strcmp. –  phpisuber01 Apr 9 at 17:35
 
What do you mean with comparing only one (1) field? $arr1['field_x1'] === $arr2['filed_x2']? –  djot Apr 9 at 17:38
1  
Besides, you should always get a "they are different" because your else part misses brackets {} –  djot Apr 9 at 17:40

1 Answer

up vote 0 down vote accepted

You will need to check the arrays against each other: 

$Array_1 = array (1,2,3,4,5);
$Array_2 = array(1,2,3,4,5,6);

print_r(array_diff($Array_1,$Array_2));

Will output: 

Array
(
)

Whereas: 

 print_r(array_diff($Array_2,$Array_1));

will output: 

Array
(
    [5] => 6
)

So this might be a solution: 

function ArrayDiff ($Array_1, $Array_2){
    $Compare_1_To_2 = array_diff($Array_1,$Array_2);
    $Compare_2_To_1 = array_diff($Array_2,$Array_1);
    $Difference_Array = array_merge($Compare_1_To_2,$Compare_2_To_1);
    return $Difference_Array;

}

print_r(ArrayDiff($Array_1,$Array_2));

Which will output: 

Array
(
    [0] => 6
)

Putting this into an if statement: 

$Differences = ArrayDiff($Array_2,$Array_1);
if (count($Differences) > 0){
    echo 'There Are Differences Between The Array:';
    foreach ($Differences AS $Different){
        echo "<br>".$Different;
    }

All the examples and code is based off the arrays at the start ($Array_1 and $Array_2)

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