php echo from array_chunk as string - php

Question

I want to echo an array_chunk as string, how do I do that ?
here is the code
$rt = $this->db->query("SELECT id_reg_pd FROM 043104_kuliahmhs_20152_2a0dc380_temp");
$_datao = array_chunk($rt->result(), 3);
foreach($_datao as $batman => $robin) {
print_r($robin);
}
I want echo id_reg_pd as string.
I have tried tried :
echo $robin->id_reg_pd;
but get php error like this
A PHP Error was encountered
Severity: Notice
Message: Trying to get property of non-object
Here the array from print_r($robin);
Array
(
[0] => stdClass Object
(
[id_reg_pd] => 001be76b-4e58-4cea-96cf-fee2d8e0abdc
)
[1] => stdClass Object
(
[id_reg_pd] => 001d4fe5-73f5-4bae-b126-1f787ea0104e
)
[2] => stdClass Object
(
[id_reg_pd] => 002ab28b-e0b9-464a-89fb-12552512a5d0
)
)

Answer 1

Loop over $robin and then check
foreach($robin as $value)
{
echo $value->id_reg_pd;
}

Answer 2

try like this
for($i=0;$i<count($_datao);$i++){
$newarr = (array) $robin[$i];
echo $newarr['id_reg_pd'];
}

Answer 3

Sahil is incorrect. It is not true that you must use a for / foreach loop to achieve your desired result. array_column() works on an array of objects. If you can use a simple implode() call to convert your array to a string, then here is a simple one-liner:
Code (Demo):
$robin=[
(object)['id_reg_pd'=>'001be76b-4e58-4cea-96cf-fee2d8e0abdc'],
(object)['id_reg_pd'=>'001d4fe5-73f5-4bae-b126-1f787ea0104e'],
(object)['id_reg_pd'=>'002ab28b-e0b9-464a-89fb-12552512a5d0']
];
//print_r($robin); // uncomment to see for yourself
//var_export(array_column($robin,'id_reg_pd')); // uncomment to see for yourself
echo implode(', ',array_column($robin,'id_reg_pd')); // implode with whatever glue you wish
Output:
001be76b-4e58-4cea-96cf-fee2d8e0abdc, 001d4fe5-73f5-4bae-b126-1f787ea0104e, 002ab28b-e0b9-464a-89fb-12552512a5d0