在XML地址中插入外部变量（连接）

So its me again, i'm facing a wired issue while calling an external XML file into my PHP code. Thing is, same way of concatenating a variable with URL and then calling the URL as json works fine but when i try to concatenate a variable in URL of XML, it returns error. Here is what works fine (json):

$city = input[1]; // Input is an external input...
$liveWeather = file_get_contents("http://weather3.pricop.info/api.php?city=$city");

Here is XML one which does 'not' works:

$city = input[1];
$xmlString = file_get_contents("http://api.openweathermap.org/data/2.5/forecast/daily?q=$city&mode=xml&units=imperial&cnt=9");
$xml = new SimpleXMLElement($xmlString);

And the error is:

Warning: SimpleXMLElement::__construct(): Entity: line 1: parser error : Start tag expected, '<' not found in /home/u369795042/public_html/weather.php on line 18

Maybe its a dumb question but i tried finding about that around and couldn't find this simple problem's issue.

Use:

$xml = simplexml_load_string($xmlString);

I've made this php file and it worked fine:

<?php
error_reporting(E_ALL);
$city = "New+York";
$xmlString = file_get_contents("http://api.openweathermap.org/data/2.5/forecast/daily?q=$city&mode=xml&units=imperial&cnt=9");
$xml=simplexml_load_string($xmlString);
print_r($xml);
unset($xml);
exit();
?>

Can you try this?