php add a new data in a json tree

Question

How can I add new data to a JSON structure?

Here is the JSON in json.txt:

[
 {"name":"foo","number":"1"},
 {"name":"bar","number":"2"},
 {"name":"Hello","number":"3"}
]

Now I want to add a new line {"name":"good day","number":"**"}

$file = 'json.txt';
$data = json_decode(file_get_contents($file));
$newdata = array('name'=>'good day', 'number' => '**');// how to add `number` automatic `+1`, make it to `4` with php code?
$data[] = $newdata;
file_put_contents($file, json_encode($data));

4 because it will be the fourth entry in the array, or because it's the max number (3) + 1? — Yoshi
– Yoshi, Commented Jul 19, 2011 at 18:45
@Yoshi, if I add more datas in this txt, and how to insert the number automaticlly increase? — fish man
– fish man, Commented Jul 19, 2011 at 18:47
It looks to me like this number property should not exist. The subobjects already have a natural ordering, so remove the redundant and hard-to-maintain number field and lose nothing. — Lightness Races in Orbit
– Lightness Races in Orbit, Commented Jul 19, 2011 at 18:49

phihag · Accepted Answer · 2011-07-19 18:52:35Z

2

$file = 'json.txt';
$data = json_decode(file_get_contents($file));
$newNumber = max(array_map(
   function($e) {return intval($e['number']);},
$data)) + 1;
$newdata = array('name'=>'good day', 'number' => strval($newNumber));
$data[] = $newdata;
file_put_contents($file, json_encode($data));

In php < 5.3, replace the $newNumber = statement with:

$newNumber = max(array_map(
    create_function('$e', 'return intval($e["number"]);'),
$data)) + 1;

edited Jul 19, 2011 at 18:52

answered Jul 19, 2011 at 18:46

phihag

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2 Comments

fish man Over a year ago

Parse error: syntax error, unexpected T_FUNCTION, expecting ') on line 4

phihag Over a year ago

@fish man I'm assuming you're testing with an old php version. Updated the answer with code that should work for php<5.3 too.

yuli chika · Accepted Answer · 2011-07-19 19:34:35Z

1

In your example, the number is continuous. Why not use end make the number auto increase?

<?php
$file = 'json.txt';
$data = json_decode(file_get_contents($file));
$number = (end($data)->number) + 1;
$newdata = array('name'=>'good day', 'number' => ''.$number.''); // how to add `number` automatic `+1`, make it to `4` with php code?
$data[] = $newdata;
file_put_contents($file, json_encode($data));
?>

answered Jul 19, 2011 at 19:34

yuli chika

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