Question

I’m using a NSSortDescriptor to sort my tableView but this line is making trouble:

if (buttonIndex == 0) {
    sortDesc = [[NSSortDescriptor alloc] initWithKey:@"Rate" ascending:NO];
}

“Rate” is a Number string in a plist (array with dictionaries).

If dictionary is unrated, default value is “0” and if it is rated, value is “1”, “2”, “3”, “4”, “5” or “6”. Why can’t I sort by these values, and how to do so?

‘NSInvalidArgumentException’, reason: ‘-[__NSCFNumber length]:
unrecognized selector sent to instance 0x6c382c0’

EDIT:

The problem is that I am rating the dictionary with a string instead of Number:

[mutDict setValue:@"0" forKey:@"Rate"];

How to set a number for Rate instead of string?

Answer 1

How to set a number for Rate instead of string?

You can use NSNumber instead of a string literal:

[mutDict setValue:[NSNumber numberWithInt:0] forKey:@"Rate"];
//          The actual rate goes here ----^

Other class methods for NSNumber include numberWithLong, numberWithDouble, and NumberWithFloat.