How can I update json data if it meets certain conditions?

Question

My json data is like this :

$json_data = '{"2": "1", "3": "3"}';

Note :

2 = star, 1 = user, 3 = star, 3 = user

If I have variables like this :

$user = 3;
$star = 4;

I want check variable $user exist in $json_data or not

If exist, it will update to be :

$json_data = '{"2": "1", "4": "3"}';

So, if $user exist in $json_data, it will update $star

I try like this :

<?php
    $user = 3;
    $star = 4;
    $json_data = '{"2": "1", "3": "3"}';
    $array_data = json_decode($json_data, true);
    if(in_array($user, $array_data))
    {
        // update here
    }
?>

I'm still confused, how to update it

Is there anyone who can help me?

You wanto to update `$star`? You just, `$start = {new_value}` asign a new value to it? — Nytrix, Mar 09 '17 at 04:27
check this http://stackoverflow.com/questions/13391579/how-to-rename-json-key — Jarachanthan Ratnakumar, Mar 09 '17 at 04:30
You might want to start by learning about data structures. Using surrogate keys like this in json is messy — symcbean, Mar 09 '17 at 04:45

score 2 · Accepted Answer · answered Mar 09 '17 at 04:36

You should use array_search() to check if the $user exists, and in case it does, it will return the array index.

$key = array_search($user, $array_data); // Returns 3 i.e array key where $user exists

if ($key !== false) {
    $array_data[$star] = $array_data[$key]; // If key found, set value to $array_data[4]
    unset($array_data[$key]); // Remove the previous data $array_data[3]
}

echo json_encode($array_data);

Output:

{"2":"1","4":"3"}

score 0 · Answer 2 · answered Mar 09 '17 at 04:42

I think this code help you to resolve your Query

PHP Code

<?php
$result = array();
$json_data = '{"2": "1", "3": "3"}';
$user = 3;
$star = 4;
$dataArray = json_decode($json_data, true);
foreach($dataArray as $key=>$val) {
    if($val == $user) {
        $result[$star] = $val ;
    } else {
        $result[$key] = $val ;
    }
}
echo "<pre>";
print_r (json_encode($result));
?>

How can I update json data if it meets certain conditions?

2 Answers2

I think this code help you to resolve your Query