updating a json using php

Question

I have a json file which I need to update its numerical values and write back to new file.This is the sample script I have

[
  {
    "type": "flipImage",
     "image": "img/new.jpg",
     "trigger": "{{10,80},{300,350}}",
     "animationDuration": "1.0"
   }
 ]

The numerical values of "trigger": "{{10,80},{300,350}}" need to update to some other value. I am managed to get the value by json_decode() in php . After decoding it is returning the value {{10,80},{300,350}}

This is script for decoding

$json_data  = file_get_contents('json.txt');    
$encoded_data = json_decode($json_data,true);   
echo $encoded_data[0]['trigger'];

But I got stuck in the updating part . How can I split the value, then update and write back the updated json file?

Any help highly appreciable.

Update First I need parse that numerical values then I have some calculations on it. After calculation write back the entire json to new file

You don't need to parse {{10,80},{300,350}} if you just want to overwrite it, do you? — Álvaro González
– Álvaro González, Commented Aug 13, 2013 at 9:54
@ÁlvaroG.Vicario First I need parse that value then I have some calculations on it. After calculation write back the entire json to new file — Anish
– Anish, Commented Aug 13, 2013 at 9:57

Álvaro González · Accepted Answer · 2013-08-13 10:09:20Z

1

If you're kind of sure that you won't find variations on the format, it's quite a simple regular expression (escaping makes it look harder than it is):

<?php

$input = '{{10,80},{300,350}}';
$output = null;

if( preg_match('/^\{\{(\d+),(\d+)\},\{(\d+),(\d+)\}\}$/', $input, $matches) ){
    // Example: increment all numbers in 1
    $matches[1]++;
    $matches[2]++;
    $matches[3]++;
    $matches[4]++;

    $output = sprintf('{{%d,%d},{%d,%d}}', $matches[1], $matches[2], $matches[3], $matches[4]);
}

var_dump($output);

answered Aug 13, 2013 at 10:09

Álvaro González

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1 Comment

Anish Over a year ago

Thanks for your great answer. It works for me. I need to look into the regular expressions.

Mario Dian · Accepted Answer · 2013-08-13 10:03:50Z

1

With file updating:

<?php
$file = 'json.txt';
$json_data = file_get_contents($file);    
$encoded_data = json_decode($json_data,true);  

$encoded_data[0]['trigger'] = "{{X,Y},{X,Y}}"; // New value

// Update file
$fp = fopen($file, 'w+');
fputs($fp, json_encode($encoded_data));
fclose($fp);
?>

answered Aug 13, 2013 at 10:03

Mario Dian

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Comments

Rohan Kumar · Accepted Answer · 2013-08-13 10:14:29Z

0

Try this

If the values are fixed(4) only then create 4 variables like

$tr=$encoded_data[0]['trigger'];
$x1=$tr[0][0];
$y1=$tr[0][1];
$x2=$tr[1][0];
$y2=$tr[1][1];
// do calculations here
$encoded_data[0]['trigger']="{{$x1,$y1},{$x2,$y2}}";
echo json_encode($encoded_data);

edited Aug 13, 2013 at 10:14

answered Aug 13, 2013 at 9:59

Rohan Kumar

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2 Comments

Anish Over a year ago

thanks for replying @Rohan Kumar . But first i need to parse the value and then do some calculations. That value i need to write into the php file

Álvaro González Over a year ago

Please note that trigger does not contain JSON.

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