iOS NSArray 自定义排序

源自:
http://www.jianshu.com/p/84804196972d

NSArray *array = @[@1,@2,@3,@1,@2,@5,@4];
NSArray *testArr = [array sortedArrayWithOptions:NSSortStable usingComparator:
^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
            int value1 = [obj1 intValue];
            int value2 = [obj2 intValue];
            if (value1 > value2) {
                return NSOrderedDescending;
            }else if (value1 == value2){
                return NSOrderedSame;
            }else{
                return NSOrderedAscending;
            }
        }];

这样排序可以排序任何内容, 只要比出大小就可以