php อ่านค่า json จะโยนข้อมูลภายใน json เข้าตัวแปร php ยังไงครับ ไม่เข้าใจเท่าไหร่

<?php

$json = '
{
"CustomerID":"C001",
"Name":"Weerachai Nukitram",
"Email":"[email protected]",
"CountryCode":"TH",
"Budget":"1000000",
"Used":"600000"
}
';

$obj = json_decode($json);
echo $obj->{'CustomerID'}; 

?>

<?php

$json = '
	[
	{"CustomerID":"C003","Name":"Jame Born","Email":"[email protected]","CountryCode":"US","Budget":"3000000","Used":"600000"}
	,{"CustomerID":"C004","Name":"Chalee Angel","Email":"[email protected]","CountryCode":"US","Budget":"4000000","Used":"100000"}
	]
';

$obj = json_decode($json);
foreach($obj as $val)
{
	echo $val->{'CustomerID'}."<br>"; 
}

?>

<?php

$json = '
{
"CustomerID":"C001",
"Name":"Weerachai Nukitram",
"Email":"[email protected]",
"CountryCode":"TH",
"Budget":"1000000",
"Used":"600000"
}
';

$arr = json_decode($json ,true);
echo $arr['CustomerID'];

?>