NSMutableArray 排序

http://iphone.ipsw.info/2009/10/nsmutablearray.html

- (NSArray *)sortedArrayUsingSelector:(SEL)comparator

Parameters
comparator
A selector that identifies the method to use to compare two elements at a time. The method should return

NSOrderedAscending

if the receiver is smaller than the argument,

NSOrderedDescending

if the receiver is larger than the argument, and

NSOrderedSame

if they are equal

NSArray *sortedArray =

[anArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

@property (nonatomic, readwrite, retain) NSMutableArray *parameters;

[self.parameters sortUsingSelector:@selector(compare:)];

#pragma mark -

- (NSComparisonResult)compare:(id)inObject {

NSComparisonResult result = [self.name compare:[(MPURLRequestParameter *)inObject name]];

if (result == NSOrderedSame) {

result = [self.value compare:[(MPURLRequestParameter *)inObject value]];

}

return result;

}

//////////////////////////////////////////////////////////

sortedArrayUsingFunction:适合基本类型（支持compare方法）

#pragma mark SORT METHOTDS

NSInteger sortObjectsByLatestTime(id obj1, id obj2, void *context)

{

NSDate* d1 = [(MessageGroup*)obj1 latestTime];

NSDate* d2 = [(MessageGroup*)obj2 latestTime];

//sort by desc

return [d2 compare:d1];

}

NSInteger dateSort(id obj1, id obj2, void *context)

{

NSDate* d1 = ((Inbox*)obj1).datetime;

NSDate* d2 = ((Inbox*)obj2).datetime;

return [d1 compare:d2];

}

////////////////////////////////////////////////////////////////////

-(NSArray*)sortedMessages

{

return [[groupMessages allValues] sortedArrayUsingFunction:sortObjectsByLatestTimecontext:NULL];

}

//////////////////////////////////////////////////////////

sortUsingDescriptors:适合元素是dict类型，initWithKey既是dict key.

NSMutableArray *regions = [NSMutableArray array];

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];

NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];

[regions sortUsingDescriptors:sortDescriptors];

[sortDescriptor release];