Extracting a specific part of a string - php

Question

I have this string:
[25-03-15, 1236], [26-03-15, 3000], [27-03-15, 3054], [30-03-15, 4000]
I want to get two parts from it as below:
['25-03-15','26-03-15','27-03-15','30-03-2015']
and
[1236,3000,3054,4000]
Please guide me how I can perform this task.
PS: I am working of view page of codeigniter.
I'm getting the first thing as:
<?php
$usd=$this->db->query('select transaction_date, SUM(amount) as total
from transactions GROUP BY transaction_date')->result_array();
$str = '';
for($i=0; $i<count($usd); $i++){
if($i!=0){
$str = $str.', ['.date('d-m-y', strtotime($usd[$i]["transaction_date"])).', '.$usd[$i]["total"].']';
}else{
$str = $str.'['.date('d-m-y', strtotime($usd[$i]["transaction_date"])).', '.$usd[$i]["total"].']';
}
}
echo $str;
?>

Answer 1

Try this..
$date = '';
$total = '';
for($i=0; $i<count($usd); $i++){
if($i!=0){
$date .= date('d-m-y', strtotime($usd[$i]["transaction_date"])).', ';
$total .= $usd[$i]["total"].', ';
}else{
$date .= date('d-m-y', strtotime($usd[$i]["transaction_date"])).', ';
$total .= $usd[$i]["total"].', ';
}
}
echo $finaldate='['. $date.']';
echo $finaltotal='['. $total.']';

Answer 2

I don't see any reason why you need to save this data from your db in a string. Just save it in an array and it is that easy:
So here I save your data in an array, so that you get this structure:
array(
array(25-03-15, 1236),
array(26-03-15, 3000),
array(27-03-15, 3054),
array(30-03-15, 4000)
)
The you can simply use array_column() to extract the single columns, like this:
<?php
$usd = $this->db->query('select transaction_date, SUM(amount) as total
from transactions GROUP BY transaction_date')->result_array();
foreach($usd as $k => $v)
$result[] = [date('d-m-y', strtotime($usd[$k]["transaction_date"])), $usd[$k]["total"]];
$partOne = array_column($result, 0);
$partTwo = array_column($result, 1);
?>
Also if you then need this data in a string as you said in the comments you can simply transform it:
I will pass this extracted data to a graph that accepts this kind of data – Shahid Rafiq 6 mins ago
Just use this:
echo $str = "[" . implode("],[", array_map(function($v){
return implode(",", $v);
}, $usd)) . "]";
output:
[25-03-15, 1236], [26-03-15, 3000], [27-03-15, 3054], [30-03-15, 4000]
EDIT:
If you also want the parts as string just simply do this:
$partOne = "[" . implode("],[", array_column($arr, 0)) . "]";
$partTwo = "[" . implode("],[", array_column($arr, 1)) . "]";
output:
[25-03-15],[26-03-15],[27-03-15],[30-03-15]
[1236],[3000],[3054],[4000]