Cocoa Programming for OS X: The Big Nerd Ranch Guide

For the More Curious: Filtering

As discussed earlier, NSArrayController arranges its objects by filtering and sorting. These two lenses correspond to properties on NSArrayController: filterPredicate, an NSPredicate, and sortDescriptors, an array of NSSortDescriptor objects.

NSPredicate is a logical operator that can be evaluated against an object. Predicates are typically instantiated using a format string. This predicate evaluates to true when raise is above 5%:

if let raisePredicate = NSPredicate(format: "raise > 0.05") {
    let matched: Bool = raisePredicate.evaluateWithObject(employee)
    ...
}

You can also create an array by filtering another. This predicate performs a case-insensitive comparison on the name and requires that ...