Use NSSortDescriptor like this.. NSSortDescriptor * descriptor = [[NSSortDescriptor alloc] initWithKey:@”interest” ascending:YES]; stories = [stories sortedArrayUsingDescriptors:@[descriptor]]; recent = [stories copy]; stories is the array you want to sort. recent is another mutable array which has sorted dictionary values. Change the @”interest” with the key value on which you have to sort. All the best
id object = myArray[0];// similar to [myArray objectAtIndex:0] if(![object isEqual:[NSNull null]]) { //do something if object is not equals to [NSNull null] }
To add on the other answers, you can use -[NSArray reverseObjectEnumerator] in combination with the fast enumeration feature in Objective-C 2.0 (available in Leopard, iPhone): for (id someObject in [myArray reverseObjectEnumerator]) { // print some info NSLog([someObject description]); } Source with some more info: http://cocoawithlove.com/2008/05/fast-enumeration-clarifications.html
Take a look here: Creating and Using Sort Descriptors You can compare as case-insensitive. NSSortDescriptor *sorter = [[[NSSortDescriptor alloc] initWithKey:@”w” ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease]; NSArray *sortDescriptors = [NSArray arrayWithObject: sorter]; [mGlossaryArray sortUsingDescriptors:sortDescriptors];
id object = [[[self.array objectAtIndex:index] retain] autorelease]; [self.array removeObjectAtIndex:index]; [self.array insertObject:object atIndex:newIndex]; That’s all. Taking care of the retain count is important, since the array might be the only one referencing the object.
Yes, hard-coded NSStrings (string literals) (that is any @”…” in your source code) are turned into strings that exist indefinitely while your process is running. However NSArray‘s containsObject: methods calls isEqual: on its objects, hence even a dynamically created string such as [NSString stringWithFormat:@”%d”, 2] would return YES in your sample snippet. This is because … Read more
Could you store strings and use NSSelectorFromString? From the docs NSSelectorFromString Returns the selector with a given name. SEL NSSelectorFromString ( NSString *aSelectorName );
If I have an NSMutableArray of objects with a field “beginDate” of type NSDate I am using an NSSortDescriptor as below: NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@”beginDate” ascending:TRUE]; [myMutableArray sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]]; [sortDescriptor release];
The stop argument to the Block allows you to stop the enumeration prematurely. It’s the equivalent of break from a normal for loop. You can ignore it if you want to go through every object in the array. for( id obj in arr ){ if( [obj isContagious] ){ break; // Stop enumerating } if( ![obj … Read more
NSValue doesn’t only support CoreGraphics structures – you can use it for your own too. I would recommend doing so, as the class is probably lighter weight than NSData for simple data structures. Simply use an expression like the following: [NSValue valueWithBytes:&p objCType:@encode(Megapoint)]; And to get the value back out: Megapoint p; [value getValue:&p];