Question

I have an array of objects that i want to sort by two keys. The objects lets say are of type Student and the properties that i’m intrested in for my sort are grade and name.

Student
{
    double grade;
    string name;
    ...
} 

How can i sort the objects first by grade and then by name? so for example if i have the list:
Tom 9.9
Andrew 9.8
Chriestie 10
Mat 9.8
Allison 10
Ada 9.8

After the sort i should have:
Allison 10
Christie 10
Tom 9.9
Ada 9.8
Andrew 9.8
Mat 9.8

And not
Christie 10
Allison 10
Tom 9.9
Andrew 9.8
Ada 9.8
Mat 9.8

any pointer is really helpful.

Answer 1

I’m pretty flakey on my objective-c knowledge but there’s some good pointers here and there’s always the documentation. Here’s my crack at it…

NSSortDescriptor *gradeSorter = [[NSSortDescriptor alloc] initWithKey:@"grade" ascending:YES];
NSSortDescriptor *nameSorter = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];

[personList sortUsingDescriptors:[NSArray arrayWithObjects:gradeSorter, nameSorter, nil]];