Question

我有一个带有大量字符串的文件，如下所示：

 item1,01-SR,admin,Missing or broken,undefined, 16/04/2013 18:10:10;
 item1,03-SR,admin,In Use,undefined, 16/04/2013 18:10:34;
 item1,01-SR,admin,In Use,undefined, 16/04/2013 18:10:45;
 item1,02-SR,admin,In Use,undefined, 16/04/2013 18:10:49;
 item1,05,admin,In Use,undefined, 16/04/2013 18:10:56;

我正在读取字符串然后将它们拆分，所以我一次只得到一个字符串。然后我想拆分我再次获得的字符串，因此每个CSV都是它自己的变量。我这样尝试过（numLines是文件中行数的计数）：

 while (count1 < numLines) {
      NSString *message = [[strings objectAtIndex: count1] copy];

      NSMutableArray *items = [[fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@";"]] mutableCopy];

      NSString *items1 = [[items objectAtIndex: count1] copy];

      NSLog(@"items: %@", items1);

      NSMutableArray *inditems = [[items1 componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@","]] mutableCopy];

      NSString * item1 = inditems[0];
      NSString * bnum1 = inditems[1];
      NSString * user1 = inditems[2];
      NSString * state1 = inditems[3];
      NSString * gender1 = inditems[4];
      NSString * tstamp1 = inditems[5];

      NSLog(@"item: %@", item1);
      NSLog(@"bnum: %@", bnum1);
      NSLog(@"user: %@", user1);
      NSLog(@"state: %@", state1);
      NSLog(@"gender: %@", gender1);
      NSLog(@"tstamp: %@", tstamp1);

      count1++;
}

现在，这可以从文件中选择一行，并将前两个项放入数组，然后将item1和bnum1的值写入日志，但由于某种原因它会抛出异常。现在这通常会告诉我数组中不存在第2项，所以我做了一个计数：

 NSLog(@"count = %d", [inditems count]);

哪个正确返回6.然后我想检查它是否可以实际读取数组中的另一个项目，所以我做了：

 NSString *tstamp1 = [[inditems lastObject] copy];

正确记录时会返回如下所示的时间戳：

 16/04/2013 18:10:10

所以我想“哦，至少第5项工作”并尝试获得该项目：

 while (count1 < numLines) {
      NSString *message = [[strings objectAtIndex: count1] copy];

      NSMutableArray *items = [[fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@";"]] mutableCopy];

      NSString *items1 = [[items objectAtIndex: count1] copy];

      NSLog(@"items: %@", items1);

      NSMutableArray *inditems = [[items1 componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@","]] mutableCopy];

      NSString * item1 = inditems[0];
      NSString * bnum1 = inditems[1];
      NSString * tstamp1 = inditems[5];

      NSLog(@"item: %@", item1);
      NSLog(@"bnum: %@", bnum1);
      NSLog(@"tstamp: %@", tstamp1);

      count1++;
}

但这也引发了异常！我可能在这里做了一些愚蠢的事情，但我会感激任何帮助。

谢谢！

Answer 1

我的猜测是你的NSArray *字符串包含空值，导致你的错误。你需要先检查它，然后再做你的逻辑。

//path is your file path
NSString* fileContents = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
NSArray *strings = [fileContents componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];
for (int i = 0; i < [strings count]; i++){
   if (![[strings objectAtIndex:i] isEqualToString:@""]){
   //Here do your code...
   }
}

从NSMutableArray读取即使它存在，也会在第2项引发异常

1 个答案: