How to sort NSArray of objects based on one attribute

I am trying to sort an array of mana开发者_如何转开发ged objects alphabetically. The attribue that they need to be sorted by is the name of the object (NSString) with is one of the managed attributes. Currently I am putting all of the names in an array of strings and then using sortedNameArray = [sortedNameArray sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)]; and then enumerating them back into an array with the objects. This falls apart when two names are the same so I really need to be able to sort by one attribute. How should I go about doing this?

Use NSSortDescriptor. Just search the documentation on it and there some very simple examples you can copy right over. Here is a simplified example:

NSSortDescriptor *valueDescriptor = [[NSSortDescriptor alloc] initWithKey:@"MyStringVariableName" ascending:YES];
NSArray *descriptors = [NSArray arrayWithObject:valueDescriptor]; 
NSArray *sortedArray = [myArray sortedArrayUsingDescriptors:descriptors]; 

And just like that you have a sorted array.

You can do this by using NSSortDescriptor,

eg.

`NSSortDescriptor *valueDescriptor = [[NSSortDescriptor alloc]initWithKey:@"distance" ascending:YES];`

// Here I am sorting on behalf of distance. You should write your own key.

NSArray * descriptors = [NSArray arrayWithObject:valueDescriptor];
NSArray *sortedArray=[yourArray sortedArrayUsingDescriptors:descriptors];`