I think I've found where the error lies:

    $convertJSON = file_get_contents("http://www.google.com/ig/calculator?hl=en&q=" . $currencyValue . $currencySelectValue . "%3D%3FUSD", true);
    var_dump($convertJSON);
    $convertArr = json_decode($convertJSON, true);
    var_dump($convertArr);

I do that to debug, and I开发者_如何学JAVA get this result (I entered 555 and Euros):

string(68) "{lhs: "555 Euros",rhs: "796.64700 U.S. dollars",error: "",icc: true}"
NULL

So it seems that the PHP function to decode the JSON object is doing something wrong somewhere. Any help?

Not a direct response to this question, but an issue I spent a few hours trying to resolve.

If you are attempting to decode JSON that came from a remote file via CURL, and if that file is in UTF-8 format, the beginning of the file may have the following characters (which breaks json_decode():



Which you will not see with the naked eye, only via htmlentities(); I have no idea why they are there, I traced this all the way to curl_exec(), thinking that maybe they were being added there. In any case, those little bastards were being added only when file is in UTF-8 format.

So, assuming you have no control over the encoding of the source file, you can do something like this before passing the string into json_decode():

$encoding = mb_detect_encoding($json);

if($encoding == 'UTF-8') {
  $json = preg_replace('/[^(\x20-\x7F)]*/','', $json);    
}    

print_r(json_decode($json));

I hope I save somebody some time, it took me a few hours of tracing to figure out that's what was happening.

The response Google is giving you isn't valid JSON because the labels are not quoted. You'll have to parse it yourself.

$response = '{lhs: "555 Euros",rhs: "796.64700 U.S. dollars",error: "",icc: true';
preg_match('/rhs:\s*"([^"]+)"/', $response, $m);
echo $m[1];

Output:

796.64700 U.S. dollars

strip it of everything but decimal points, commas, and numbers, and give me a result.

Actually you do the exact contrary with your regex. Add a ^ after [: [^ to negate it

$currencyValue = preg_replace('/([^0-9\.,]+)/', '', $currencyValue);

to make json_encode workable, you have to add double quote to the result string in order to make it in JSON format.

I tries the simple code below , and it works fine:

$data = '{lhs: "1 U.S. dollar",rhs: "7.80177256 Hong Kong dollars",error: "",icc: true}';
$data = str_replace('lhs','"lhs"',$data);
$data = str_replace('rhs','"rhs"',$data);
$data = str_replace('error','"error"',$data);
$data = str_replace('icc','"icc"',$data);
print_r(json_decode($data));

Result:

stdClass Object ( [lhs] => 1 U.S. dollar [rhs] => 7.80177256 Hong Kong dollars [error] => [icc] => 1 ) 

Now it is in json_decode object!

Expanding on Matthews answer:

In case for some reason you want all data; (probably not but just in case?)

$c='{lhs: "1 British pound",rhs: "1.5358 U.S. dollars",error: "",icc: true}';
$j=json_decode(preg_replace('/({|,)([a-z]+): /','$1"$2": ',$c));
var_dump($j->{'rhs'});

I stumbled across this page before I worked it out so maybe others will too :)