How can I optimize this loop?

Question

I've got a piece of code that returns a super-long string that represents "search results". Each result is represented by a double HTML break symbol. For example:

Result1<br><br>Result 2<br><br>Result3

I've got the following loop that takes each result and puts it into an array, stripping out the break indicator, " kBreakIndicator " (<br><br>). The problem is that this lopp takes way too long to execute. With a few results it's fine, but once you hit a hundred results, it's about 20-30 seconds slower. It's unacceptable performance. What can I do to improve performance?

Here's my code:

content is the original NSString.

  NSMutableArray *results = [[NSMutableArray alloc] init];

  //Loop through the string of results and take each result and put it into an array
   while(![content isEqualToString:@""]){
   NSRange rangeOfResult = [content rangeOfString:kBreakIndicator];
   NSString *temp = (rangeOfResult.location != NSNotFound) ? [content substringToIndex:rangeOfResult.location] : nil; 
   if (temp) {
    [results addObject:temp];
    content = [[[content stringByReplacingOccurrencesOfString:[NSString stringWithFormat:@"%@%@", temp, kBreakIndicator] withString:@""] mutableCopy] autorelease];
   }else{
    [results addObject:[content description]];
    content = [[@"" mutableCopy] autorelease];
   }
  }
//Do something with the results array.
[results release];

Answer 1

What you can do is first use NSString 's componentsSeparatedByString: method that will give you an NSArray , like this:

EDIT: Assuming your kBreakIndicator constant is <br> :

NSArray *temp_results = [content componentsSeparatedByString:kBreakIndicator];
NSMutableArray *results = [[NSMutableArray alloc] init];
for(NSString *result in temp_results) {
   if(result.length == 0) continue;
   [results addObject:result];
}
//do something with results...
[results release];

Result of @invariant's answer : http://cl.ly/3Z112M3z3K1V2t0A3N2L

Result of my answer : http://cl.ly/371b2j2H0Y1E110D2w0I

If your kBreakIndicator constant is <br><br> :

NSArray *result = [content componentsSeparatedByString:kBreakIndicator];

Answer 2

应该这样做：

NSArray *results = [content componentsSeparatedByString:@"<br><br>"];