How to make variable that's in an array format into an array - php

Question

This is probably a simple question, but how do I take a variable like the following and make it into an array.
$hot = "It","is","hot","outside";
Doing the following doesn't work:
$newhot = array($hot);
I'm actually calling an API that looks like:
[["P0010001","NAME","state","zip code tabulation area"],
["68191","ZCTA5 99301","53","99301"]]
What I need is the population on the second line (first quotes).
Doing the following gives me "68191","ZCTA5 99301","53","99301"
$splitContent = implode("\n",array_slice(explode("\n",$populate),1,2));
$newContent = str_replace(']','',$splitContent);
$newContent = str_replace('[','',$newContent);

Answer 1

This
$hot = "It","is","hot","outside";
will generate error in PHP. But let's say you have the following retrieved from the API:
$str='[["P0010001","NAME","state","zip code tabulation area"],["68191","ZCTA5 99301","53","99301"]]';
then, if you run this line:
$myArray = json_decode($str);
and then
echo "<pre>";
print_r($myArray);
echo"</pre>";
you can have this result:
Array
(
[0] => Array
(
[0] => P0010001
[1] => NAME
[2] => state
[3] => zip code tabulation area
)
[1] => Array
(
[0] => 68191
[1] => ZCTA5 99301
[2] => 53
[3] => 99301
)
)
Second line of data will be stored in
$myArray[1]

Answer 2

Defining an array is something like...
$hot = array("It","is","hot","outside");
Re: Your Api call...
$ApiResponse = '[["P0010001","NAME","state","zip code tabulation area"],["68191","ZCTA5 99301","53","99301"]]';
$Response = json_decode($ApiResponse);
$Data = $Response[1];
Specifically, the api is returning a list of lists. We're taking the 2nd (0-indexed) list. $Data will now be the same as if you'd declared...
$Data = array("68191","ZCTA5 99301","53","99301");
Edit: Tested Code...
$Key = '[Your Key]';
$ApiResponse = file_get_contents("http://api.census.gov/data/2010/sf1?key={$Key}&get=P0010001,NAME&for=zip+code+tabulation+area:99301&in=state:53");
print "Raw: " . print_r($ApiResponse, true) . "<hr/>";
$Response = json_decode($ApiResponse);
$Data = $Response[1];
print "Extracted Data: " . print_r($Data, true) . "<br/>";
print "First bit of data: {$Data[0]}.<br/>";
print "Second bit of data: {$Data[1]}.<br/>";