Question

我正在使用以下代码将JSON数据转换为NSString：

  NSString *json_string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"Data AS STRING %@", json_string);

以这种格式返回NSString：

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
    }
}

我需要从该字符串中获取“USDGBP”的值。我怎样才能做到这一点？最好存储为double。

Answer 1

尝试使用

在NSDictionary中转换它，而不是将其转换为NSString

NSError *error;
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];

然后您可以检索USDGBP的值

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

您应该使用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];

}

如果您想获得很多乐趣，请使用NSScanner来解析字符串;）

Answer 4

你可以在字符串中找到值，只需提取2个字符串之间的字符串。

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];

NSString JSON - 通过数据过滤

4 个答案: