passing a variable from a JSON array in Objective-C - objective-c

Question

I am pulling information from a web page into my app in the form of JSON arrays. The arrays themselves are not static in that some of the items in the arrays will change from time to time. The first array contains various fields but the problem in this case is that it will send a variable which has to be passed to a different function elsewhere in my code to form part of a url. For example, the first array would be something like:
{"i_one":"some info","i_two":"some more info","p_id":"3"}]
The p_id part, i.e.:3, needs to be passed into the example url shown below to replace the {ID}.
"http://http://www.somesite.com/json/files/project_%#",p_id
How can I do this when the variable(s) received from the array are only available within the function that the array is parsed in?
Ok so,
First the array is pulled from a url via this:
#define getDataURL #"http://www.somesite.com/json/files/jarray.txt"
Then the data is retrieved and parsed like this:
//Retrieve data
NSURL * url = [NSURL URLWithString:getDataURL];
NSData * data = [NSData dataWithContentsOfURL:url];
jsonArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
//Loop through Json Array
for (int i = 0; i < jsonArray.count; i++)
{ NSString * bID= [[jsonArray objectAtIndex:i] objectForKey:#"p_id"];}
This seems to work fine to this point.
However, elsewhere in the code in another function, I then try to use p_id and pass it into a url like this:
NSString *imageUrl = NSString stringWithFormat:#"http://www.somesite.com/json/files/project_%# ", [bID];
[NSURLConnection sendAsynchronousRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:imageUrl]] queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
cell.ThumbImage.image = [UIImage imageWithData:data];}];
At this point I get "use of undeclared identifier bID"

Answer 1

OK, first off. Your array is actually a dictionary.
Using NSJSONSerialization will give you an object like...
NSDictionary *dictionary = #{
#"i_one" : #"some info",
#"i_two" : #"some more info",
#"p_id" : #"3"
};
To put the pid into a string you can use this...
NSString *string = [NSString stringWithFormat:#"http://www.somesite.com/json/files/project_%#", dictionary[#"p_id"]];