NSString JSON - filtering through data - ios

Question

I am converting JSON data in to NSString using below code:
NSString *json_string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"Data AS STRING %#", json_string);
it returns NSString in this format:
Data AS STRING
{
"success": true,
"terms": "https://currencylayer.com/terms",
"privacy": "https://currencylayer.com/privacy",
"timestamp": 1446673809,
"source": "USD",
"quotes": {
"USDAED": 3.672993,
"USDAFN": 64.980003,
"USDALL": 127.164497,
"USDAMD": 474.480011,
"USDANG": 1.790326,
"USDAOA": 135.225006,
"USDARS": 9.536025,
"USDAUD": 1.398308,
"USDAWG": 1.79,
"USDAZN": 1.04625,
"USDBAM": 1.800851,
"USDBBD": 2,
"USDBDT": 78.666946,
"USDBGN": 1.80115,
"USDBHD": 0.37727,
"USDBIF": 1562.5,
"USDBMD": 1.00005,
"USDBND": 1.403198,
"USDBOB": 6.899293,
"USDBRL": 3.80025,
"USDBSD": 0.999335,
"USDBTC": 0.002372,
"USDBTN": 65.495003,
"USDBWP": 10.55195,
"USDBYR": 17415,
"USDBZD": 1.994983,
"USDCAD": 1.315225,
"USDCDF": 929.999946,
"USDCHF": 0.99331,
"USDCLF": 0.024598,
"USDCLP": 692.094971,
"USDCNY": 6.33525,
"USDCOP": 2837.080078,
"USDCRC": 534.015015,
"USDCUC": 0.99991,
"USDCUP": 0.99978,
"USDCVE": 101.349503,
"USDCZK": 24.907012,
"USDDJF": 177.595001,
"USDDKK": 6.8657,
"USDDOP": 45.400002,
"USDDZD": 107.014999,
"USDEEK": 14.325002,
"USDEGP": 8.029699,
"USDERN": 15.279969,
"USDETB": 21.022499,
"USDEUR": 0.920471,
"USDFJD": 2.157498,
"USDFKP": 0.648499,
"USDGBP": 0.650132,
"USDGEL": 2.395014,
"USDZWL": 322.355011
}
}
I need to get value of "USDGBP" from that string. How can I do that? Preferably stored as double.

Answer 1

Rather than converting it into NSString try converting it in NSDictionary using
NSError *error;
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
then you can retrieve value of USDGBP like
double usdgbp = [jsonDict[#"quotes"][#"USDGBP"] doubleValue];

Answer 2

NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
double usdgbpValue = [jsonDict[#"quotes"][#"USDGBP"] doubleValue];

Answer 3

you can find the value in the string simply extracting a string between 2 string.
NSString *jsonStr = #"long json string";
NSRange str1 = [jsonStr rangeOfString:#"\"USDGBP\":"];
NSRange str2 = [jsonStr rangeOfString:#","];
NSRange strSub = NSMakeRange(str1.location + str1.length, str2.location - str1.location - str1.length);
NSString *valueForUSDGBP = [jsonStr substringWithRange:strSub];

Answer 4

You should use NSJSONSerialization
NSData *jsonData = your data ... ;
NSError *theError = nil;
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&theError];
if (theError) {
NSLog(#"%#", theError);
}
else {
double theValue = [jsonDict[#"quotes"][#"USDGBP"] doubleValue];
}
If you'd like to have much fun, use NSScanner to parse the string ;)