Comparing version numbers

Question

Some time ago, I read that comparing version numbers can be done using the following code snippet:

NSString *vesrion_1 = @\"1.2.1\";
NSString *version_2 = @\         


        

Answer 1

I've developed a VersionComparator on GitHub that is very light and simple to use - not as feature packed as some other solutions but easy to pick up and use.

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

It simply compares the numbers from the major to the build - if 2 is higher than 1 then there's no need to compare further.

It's aim is to provide the front-end code as simple as possible (as in the example above), and also not provide a class that has reams and reams of supporting code. More often than not, this is all that's needed.

Answer 2

NSNumericSearch should do exactly what you want. It handles all the cases you would expect from a version number. For a previous project I wrote a bunch of test cases for this:

+ (NSComparisonResult)compareBundleVersion:(NSString *)a withBundleVersion:(NSString *)b
{
    return [a compare:b options:NSNumericSearch];
}

STAssertEquals(NSOrderedSame, [self compareBundleVersion:@"1" withBundleVersion:@"1"], nil);
STAssertEquals(NSOrderedSame, [self compareBundleVersion:@"1.0" withBundleVersion:@"1.0"], nil);
STAssertEquals(NSOrderedSame, [self compareBundleVersion:@"1.1.12" withBundleVersion:@"1.1.12"], nil);

STAssertEquals(NSOrderedAscending, [self compareBundleVersion:@"1" withBundleVersion:@"2"], nil);
STAssertEquals(NSOrderedAscending, [self compareBundleVersion:@"1" withBundleVersion:@"1.1"], nil);
STAssertEquals(NSOrderedAscending, [self compareBundleVersion:@"1.0" withBundleVersion:@"1.1"], nil);
STAssertEquals(NSOrderedAscending, [self compareBundleVersion:@"1.1.12" withBundleVersion:@"1.1.13"], nil);
STAssertEquals(NSOrderedAscending, [self compareBundleVersion:@"1.1.12" withBundleVersion:@"1.2.1"], nil);

STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.1" withBundleVersion:@"1"], nil);
STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.1" withBundleVersion:@"1.0"], nil);
STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.1.13" withBundleVersion:@"1.1.12"], nil);
STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.2.1" withBundleVersion:@"1.1.12"], nil);

I have also tested this with the previous cases mentioned by another poster:

STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.30" withBundleVersion:@"1.3"], nil);
STAssertEquals(NSOrderedDescending, [self compareBundleVersion:@"1.19" withBundleVersion:@"1.3"], nil);

Everything passes as you would expect.