如何根据一个属性对对象的 NSArray 进行排序

Question

I am trying to sort an array of managed 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?

Answer 1

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.

Answer 2

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];`