MySQL JSON strings with PHP. fixing commas - php

Question

I'm creating this JSON thingy and I need to remove the last comma from it. (yes I know I could do a simple way instead of making the json myself, but I need it to be like this {"1":0,"2":4,"3":1.5}) So how can I do it? (And yes I have a working way in the code but it doesent display it like I need it.)
<?php
require 'dbConnect.script.php';
$query="SELECT * FROM `trash`";
if($is_query_run=mysql_query($query)){
print "{";
while($query_execute=$query_execute=mysql_fetch_assoc($is_query_run)){
echo '<tr><td>"'.$query_execute['id'].'"</td>:<td>'.$query_execute['weight'].',</td></tr>';
//$rows = array();
//$rows[] = $query_execute;
//print json_encode($rows);
}
print "}";
}
else{
echo "query notexecuted";
}
?>

Answer 1

In your example, you can simply create an array:
$array = ["1" => 0, "2" => 4, "3" => 1.5];
$json = json_encode($array);
Since this array doesn't start with a zero (which indexed arrays does), this would give you your desired result.
If you want to start with a zero, and still get an object back:
$array = ["0" => 2, "1" => 0, "2" => 4, "3" => 1.5];
you can use the option JSON_FORCE_OBJECT as a second parameter, like this:
$array = ["0" => 2, "1" => 0, "2" => 4, "3" => 1.5];
$json = json_encode($array, JSON_FORCE_OBJECT);
This will give you:
{
"0": 2,
"1": 0,
"2": 4,
"3": 1.5
}
Read more here: http://php.net/manual/en/function.json-encode.php
It's seldom a good idea to build your own encoders/decoders for things like this. It usually gets quite complicated pretty quick, and you will spend most of your time straighten out bugs and get stuck on edge cases. It's better to read up on the native functions. They have been tried and tested for years, and are often much better in regards of performance.

Answer 2

Whilst I concur json_encode is the nicest solution for producing JSON. To produce a nice comma separated output you could use the implode function.
Set-up your elements in an array, so for example:
$data = array('"1":0', '"2":4', '"3":1.5');
Then use implode like this
$output = implode(',', $data);
Which will give you an output of the data elements in the array as a comma separated list

Answer 3

if($is_query_run=mysql_query($query)){ //Here you execute the query
while($query_execute=$query_execute=mysql_fetch_assoc($is_query_run)){ //Here you get one row from execution result
$rows = array(); //You create array into $rows, what was in $rows before will be wiped
$rows[] = $query_execute; // You insert one row you just fetch from result to $rows
print json_encode($rows); // You encode $rows (which always has only one element as you wipe it every iteration)
}
}
So, create array before loop, and encode that array after loop, adding elements to array inside a loop is ok.
-Mr_KoKa #LinusTechTips.com