iOS: Why can’t I set nil to NSDictionary value?
It wants an actual object… use NSNull [NSNull null];
nsdictionary
Store selector as value in an NSDictionary
SEL is just a pointer, which you could store in an NSValue: NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys: [NSValue valueWithPointer:@selector(foo)], @”foo”, nil]; To get the selector back, you can use: SEL aSel = [[dict objectForKey:@”foo”] pointerValue];
NSDictionary to NSData and NSData to NSDictionary in Swift
You can use NSKeyedArchiver and NSKeyedUnarchiver Example for swift 2.0+ var dictionaryExample : [String:AnyObject] = [“user”:”UserName”, “pass”:”password”, “token”:”0123456789″, “image”:0] let dataExample : NSData = NSKeyedArchiver.archivedDataWithRootObject(dictionaryExample) let dictionary:NSDictionary? = NSKeyedUnarchiver.unarchiveObjectWithData(dataExample)! as? NSDictionary Swift3.0 let dataExample: Data = NSKeyedArchiver.archivedData(withRootObject: dictionaryExample) let dictionary: Dictionary? = NSKeyedUnarchiver.unarchiveObject(with: dataExample) as! [String : Any] Screenshot of playground
How to get the duration of an audio file in iOS?
In the ‘File Attribute Keys’ of the NSFileManager class reference you can see that there is no key to use that will return the duration of a song. All the information that the NSFileManager instance gets about a file is to do with the properties of the actual file itself within the operating system, such … Read more
convert NSDictionary to NSString
You can call [aDictionary description], or anywhere you would need a format string, just use %@ to stand in for the dictionary: [NSString stringWithFormat:@”my dictionary is %@”, aDictionary]; or NSLog(@”My dictionary is %@”, aDictionary);
Sorting NSArray of dictionaries by value of a key in the dictionaries
I think this will do it: brandDescriptor = [[NSSortDescriptor alloc] initWithKey:@”brand” ascending:YES]; sortDescriptors = [NSArray arrayWithObject:brandDescriptor]; sortedArray = [myArray sortedArrayUsingDescriptors:sortDescriptors]; I pulled the code from Sort Descriptor Programming Topics. Also, Key-Value Coding comes into play, in that sortedArrayUsingDescriptors: will send a valueForKey: to each element in myArray, and then use standard comparators to sort the … Read more
How can we store into an NSDictionary? What is the difference between NSDictionary and NSMutableDictionary?
The NSDictionary and NSMutableDictionary docs are probably your best bet. They even have some great examples on how to do various things, like… …create an NSDictionary NSArray *keys = [NSArray arrayWithObjects:@”key1″, @”key2″, nil]; NSArray *objects = [NSArray arrayWithObjects:@”value1″, @”value2″, nil]; NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys]; …iterate over it for (id key in dictionary) { … Read more
Best way to sort an NSArray of NSDictionary objects?
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
Check key exists in NSDictionary
I presume that [dataArray objectAtIndex:indexPathSet.row] is returning an NSDictionary, in which case you can simply check the result of valueForKey against nil. For example: if ([[dataArray objectAtIndex:indexPathSet.row] valueForKey:@”SetEntries”] != nil) { // The key existed… } else { // No joy… }
NSDictionary Key For Value/Object? [duplicate]
-[NSDictionary allKeysForObject:] returns an NSArray of all the keys whose objects match the passed object, where “match” is determined by isEqual:.