Sort array with custom objects

Question

I'm trying to sort an array, filled with objects from a class i wrote. The class i wrote contains an NSString itself, as the "name". So what i wanna do, is to sort the array, based on the name property the objects contain. I tried the simple:

[anArray sortedArrayUsingSelecter: CaseInsensitiveCompare];

But as you can guess, it sends the caseInsensitiveCompare message to the objects itself, and it won't respond to that one.

So i'm guessing i have to make my objects able to respond to the caseInsensitiveCompare? Not quite sure how to write such a method, so any pointers would be lovely.

Thanks

Check out http://stackoverflow.com/questions/805547/how-to-sort-an-nsmutablearray-with-custom-objects-in-it — Keith OYS, Jun 04 '14 at 04:51

score 10 · Accepted Answer · answered Mar 24 '12 at 15:12

10

You can use the method sortedArrayUsingComparator:

NSArray *sortedArray = [anArray sortedArrayUsingComparator:^(MyClass *a, MyClass *b) {
    return [a.name caseInsensitiveCompare:b.name];
}];

answered Mar 24 '12 at 15:12

sch

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That worked great, thanks chap. What exactly does this do? or i don't have to worry about it? it's taking a block as an argument, right? – Seerex Mar 24 '12 at 16:29
Yes, it is using a block to sort the array. – sch Mar 24 '12 at 16:31

score 1 · Answer 2 · answered Mar 24 '12 at 15:08

You can sortedArrayUsingComparator:(NSComparator)cmptr (NSArray reference) to sort the array. For instance, if you want to sort by the name property, do the following (assuming your class is called Person):

NSArray *sortedArray = [anArray sortedArrayUsingComparator:^(id a, id b) {
    NSString *first = [(Person *)a name];
    NSString *second = [(Person *)b name];
    return [first caseInsensitiveCompare:second];
}];

Sort array with custom objects

2 Answers2