Comparing 2 json strings to find new entries

Question

I am trying to compare 2 json strings with each other to find all new entries in the list.

This is how I am comparing them:

$json = json_decode(file_get_contents("new.json"), true);
$last_json = json_decode(file_get_contents("last.json"), true);
$difference = array_diff($json, $last_json);

print_r($difference);

I am expecting it to return an array with all new entries. However, I am just getting an empty array in return.

Any help would be appreciated!

Additional information: I am also trying to compare the values of the arrays. This is how I'm trying to do that:

foreach($json["whitelist_name"] AS $json_key => $json_val) {
        foreach($last_json["whitelist_name"] AS $last_json_key => $last_json_val) {
            if($json["whitelist_name"] != $last_json["whitelist_name"]) {
                echo $json["whitelist_name"];
            }
        }
    }

However, it seems that $json["whitelist_name"] is undefined

your json decode is returning associative arrays. So array_diff_assoc might help. — Atif
– Atif, Commented May 6, 2016 at 4:59
Awesome, that made it! Do you know if it's somehow possible to find out if anyone has changed their whitelist_name though? — Martin O
– Martin O, Commented May 6, 2016 at 5:02

Atif · Accepted Answer · 2016-05-06 05:23:45Z

6

array_diff_assoc is the way to get difference of associative arrays:

$json = json_decode(file_get_contents("new.json"), true);
$last_json = json_decode(file_get_contents("last.json"), true);
$difference = array_diff_assoc($json, $last_json);

print_r($difference);

This small piece of code will find out if any whitelist_name is different in the new json than the old one

foreach($last_json as $key=>$value){
    if($value['whitelist_name'] != $json[$key]['whitelist_name']){
        // value is changed
    }else{
        // value is not changed
    }
}

edited May 6, 2016 at 5:23

answered May 6, 2016 at 5:00

Atif

2701 silver badge12 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Martin O Over a year ago

Awesome, that made it! Do you know if it's somehow possible to find out if anyone has changed their whitelist_name though?

Atif Over a year ago

To find changed values you will have to loop over array and compare it with the other to find out if they are same or not.

Atif Over a year ago

@MartinO I have updated my answer for finding out changed values

Atif Over a year ago

Glad to know it helped

Collectives™ on Stack Overflow

Comparing 2 json strings to find new entries

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related