Question

I’m trying to sort an array of version numbers that might look like this properly sorted:

1.0.1
1.1.2
1.2.0
1.10.3
2.1.1
2.2.2
2.10.2

I have an array and I do the following:

NSArray *allUpdatekeys = [allUpdatekeystmp sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

This produces a list like:

1.0.1
1.1.2
1.10.3
1.2.0
...

So I tried writing a custom selector and I got this far by looking at examples I found:

 - (NSComparisonResult)versionCompare:(NSString*) secondVersion  {
     NSArray *secondVer = [secondVersion componentsSeparatedByString:@"."];
     NSString *firstVersion = [];
     NSArray *firstVer = [firstVersion componentsSeparatedByString:@"."];
     NSUInteger firstPri = [firstVer[0] integerValue];
     NSUInteger firstSec = [firstVer[1] integerValue];
     NSUInteger firstTer = [firstVer[2] integerValue];
     NSUInteger secondPri = [secondVer[0] integerValue];
     NSUInteger secondSec = [secondVer[1] integerValue];
     NSUInteger secondTer = [secondVer[2] integerValue];
     NSLog(@"In the version compare method");
     NSLog(@"first %@ second %@ ", self, secondVersion);
     if (firstPri < secondPri) {
         return NSOrderedAscending;
     }
     else if (firstPri  secondPri) {
         return NSOrderedDescending;
     } else {
         if (firstSec < secondSec) {
             return NSOrderedAscending;
         }
         else if (firstSec  secondSec) {
             return NSOrderedDescending;
         }
         else {
             if (firstTer < secondTer) {
                 return NSOrderedAscending;
             }
             else if (firstTer  secondTer) {
                 return NSOrderedDescending;
             }
             else {
                 return NSOrderedSame;
             }
         }
     } }

My question: What is the way to reference the first version? I need what essentially is the first string from the array. I have been racking my brain to understand this, but all of the examples I have found don’t work either. I’m using Xcode 4.4 on 10.8 if that helps or matters.

Answer 1

I think localizedStandardCompare is what you’re looking for:

NSArray *theArray = [NSArray arrayWithObjects:    
                     @"1.0.1",
                     @"1.1.2",
                     @"1.2.0",
                     @"1.10.3",
                     @"2.1.1",
                     @"2.2.2",
                     @"2.10.2",
                     nil];

NSArray *sortedArray  = [[NSArray alloc] initWithArray:[theArray sortedArrayUsingSelector:@selector(localizedStandardCompare:)]];

NSLog(@"%@", sortedArray);

Output:

(
    "1.0.1",
    "1.1.2",
    "1.2.0",
    "1.10.3",
    "2.1.1",
    "2.2.2",
    "2.10.2"
)