Regex vs componentsSeparatedByCharactersInSet

main.m

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
  @autoreleasepool {
		
		NSUInteger iterations = 1000000;
		
		{ // Regex
			NSTimeInterval timeStart = CFAbsoluteTimeGetCurrent();
			NSString *result = nil;
			
			for(int i = 0; i < iterations; i++)
			{
				NSString *original = @"    Hello      this  is a   long       string!   ";
 
				NSString *squashed = [original stringByReplacingOccurrencesOfString:@"[ ]+"
				                                                     withString:@" "
				                                                        options:NSRegularExpressionSearch
				                                                          range:NSMakeRange(0, original.length)];
 
				result = [squashed stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
			}
			
			NSLog(@"Time spent on %lu iterations %f with result \"%@\"", iterations, CFAbsoluteTimeGetCurrent() - timeStart, result);
		}
		
		{ // Array separation 
			NSTimeInterval timeStart = CFAbsoluteTimeGetCurrent();
			NSString *result = nil;
			
			for(int i = 0; i < iterations; i++)
			{
				NSString *theString = @"    Hello      this  is a   long       string!   ";
 
				NSCharacterSet *whitespaces = [NSCharacterSet whitespaceCharacterSet];
				NSPredicate *noEmptyStrings = [NSPredicate predicateWithFormat:@"SELF != ''"];
 
				NSArray *parts = [theString componentsSeparatedByCharactersInSet:whitespaces];
				NSArray *filteredArray = [parts filteredArrayUsingPredicate:noEmptyStrings];
				result = [filteredArray componentsJoinedByString:@" "];
			}
			
			NSLog(@"Time spent on %lu iterations %f with result \"%@\"", iterations, CFAbsoluteTimeGetCurrent() - timeStart, result);
		}
	}
}

Console log
2013-10-18 11:39:54.239 Untitled[33067:707] Time spent on 1000000 iterations 7.679592
2013-10-18 11:40:08.026 Untitled[33067:707] Time spent on 1000000 iterations 13.786276