NSArray 排序方法的實現

Compare method

Either you implement a compare-method for your object:

-(NSComparisonResult)compare:(Person*)otherObject {return[self.birthDate compare:otherObject.birthDate];}NSArray*sortedArray;sortedArray =[drinkDetails sortedArrayUsingSelector:@selector(compare:)];

NSSortDescriptor (better)

or usually even better:

NSSortDescriptor*sortDescriptor;sortDescriptor =[[[NSSortDescriptor alloc] initWithKey:@"birthDate"                                              ascending:YES] autorelease];NSArray*sortDescriptors =[NSArray arrayWithObject:sortDescriptor];NSArray*sortedArray;sortedArray =[drinkDetails sortedArrayUsingDescriptors:sortDescriptors];

You can easily sort by multiple keys by adding more than one to the array. Using custom comparator-methods is possible as well. Have a look at the documentation.

Blocks (shiny!)

There's also the possibility of sorting with a block since Mac OS X 10.6 and iOS 4:

NSArray*sortedArray;sortedArray =[drinkDetails sortedArrayUsingComparator:^NSComparisonResult(id a, id b){NSDate*first =[(Person*)a birthDate];NSDate*second =[(Person*)b birthDate];return[first compare:second];}];