How to use compare on a version number where theres less parts in one number in Objective-C?

Question

I\'ve found the following code at http://snipplr.com/view/2771

Which is pretty good, almost exactly what I was looking for, but if I use the values @\"1.4.5\", @

Answer 1

it's simple with VersionComparator Class

https://github.com/danhanly/VersionComparator

BOOL greater = [VersionComparator isVersion:@"2.0.0" greaterThanVersion:@"1.1.0"];

Answer 2

[I posted this earlier today, but it was not selected as the answer, and it may be more appropriate to your problem. There are other techniques, you can look here and here for other solutions.]

What I do is take that string and break it into components:

NSArray *array = [myVersion componentsSeparatedByCharactersInSet:@"."];

NSInteger value = 0;
NSInteger multiplier = 1000000;
for(NSString *n in array) {
  value += [n integerValue] * multiplier;
  multiplier /= 100;
}

What this does is give you a normalized value you can use for comparison, and will generally compare releases that have different "depths", ie 1.5 and 1.5.2.

It breaks if you have more than 100 point releases (ie any number is > 100) and also will declare 1.5.0 == 1.5. That said, its short, sweet, and simple to use.

EDIT: if you use the NSString 'compare:options:' method, make sure you have your string well groomed:

    s1 = @"1.";
    s2 = @"1";
    NSLog(@"Compare %@ to %@ result %d", s1, s2, (int)[s1 compare:s2 options:NSNumericSearch]);
    s1 = @"20.20.0";
    s2 = @"20.20";
    NSLog(@"Compare %@ to %@ result %d", s1, s2, (int)[s1 compare:s2 options:NSNumericSearch]);

2012-09-06 11:26:24.793 xxx[59804:f803] Compare 1. to 1 result 1
2012-09-06 11:26:24.794 xxx[59804:f803] Compare 20.20.0 to 20.20 result 1

Answer 3

I'm not 100% sure what you're asking, but if you're looking to sort numbers regardless of how many periods "." are in the number you can use an NSSortDescriptor on a dictionary of OS versions:

NSArray *originalArray = [NSArray arrayWithObjects:
              [NSDictionary dictionaryWithObject:@"10.4.5" forKey:@"version"],
              [NSDictionary dictionaryWithObject:@"10.5.6" forKey:@"version"],
              [NSDictionary dictionaryWithObject:@"10.6.8" forKey:@"version"],
              [NSDictionary dictionaryWithObject:@"10.8" forKey:@"version"],
              [NSDictionary dictionaryWithObject:@"10.7.1" forKey:@"version"],
              [NSDictionary dictionaryWithObject:@"10.8.2" forKey:@"version"],
              nil];

NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"version" ascending:true];
NSArray *sortedArray = [originalArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:sort]];
NSLog(@"Lowest to highest: %@", sortedArray);
NSLog(@"Highest OS version: %@",[[sortedArray objectAtIndex:[sortedArray indexOfObject:[sortedArray lastObject]]] objectForKey:@"version"]);