Question

我正在尝试从使用REST查询下载的数据中的字符串中删除子字符串，我使用“stringByReplacingOccurrencesOfString”将@“Point”替换为@“”并将其存储在temp变量中，但原始变量并且temp变量没有更新。

-(void)fetchURL:(NSURL *)url
{

url = [NSURL URLWithString:@"http://team41.kmiller.io/api/getByLocation/Verizon%20Wireless/100/33.7/-84.0"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response,
                                           NSData *data, NSError *connectionError)
 {
     if (data.length > 0 && connectionError == nil)
     {
         NSDictionary *greeting = [NSJSONSerialization JSONObjectWithData:data
                                                                  options:0
                                                                    error:NULL];

         if ([[greeting objectForKey:@"result"] isEqualToString:@"success"])
         {
             NSString * temp;
             for(NSDictionary* key in [greeting objectForKey:@"json"])
             {
                 NSString * strength = [key objectForKey:@"dbm_strength"];
                 NSString * location = [key objectForKey:@"astext(location)"];
                 temp = [location stringByReplacingOccurrencesOfString:@"Point" withString:@""];
                 NSLog(@"%@",location);
                 NSLog(@"%@",temp);
                 break;
             }


             // TODO: Parse location and strength
             // TODO: Update the records to database
         }
     }
 }];
}

Answer 1

REST响应为POINT，您尝试替换Point

实际回复

"POINT(33.78272 -84.40426)"

Answer 2

虽然Vig的答案是正确的并指出一个问题，但更糟糕的是：subStringByReplacingOccurrencesOfString：返回一个新的NSString *。它不会修改消息的接收者。修改后的字符串存储在temp中，传递给NSLog，然后丢弃。此代码不会将结果存储在任何位置。

子串删除问题Objective-C

2 个答案: