CVPredicateFilter

Flexible filtering of arrays on a background thread with NSPredicate.

Usage

Add the dependency to your Podfile:

platform :ios # or :osx
pod 'CVPredicateFilter'
...

Run pod install to install the dependencies.

CVPredicateFilter

#import "CVPredicateFilter.h"

Instantiate CVPredicateFilter with the array to filter:

NSArray *objects = @[@"a cat", @"a hat", @"and", @"a band"];
CVPredicateFilter *predicateFilter = [CVPredicateFilter filterWithObjects:objects];

NSPredicate *filter = [NSPredicate predicateWithFormat:@"SELF BEGINSWITH 'an'"];

[predicateFilter pushFilter:filter withCompletionHandler:^(NSArray *filteredObjects) {
    NSLog(@"Found matches: %@", filteredObjects); // returns @[@"and"]
}];

A templatePredicate can also be used to save parsing the predicate format string every time a filter is pushed. Use a substitution variable (the one with $ in front of it):

NSArray *objects = @[@"a cat", @"a hat", @"and", @"a band"];
CVPredicateFilter *predicateFilter = [CVPredicateFilter filterWithObjects:objects templatePredicate:[NSPredicate predicateWithFormat:@"SELF BEGINSWITH[c] $searchTerm"];

// The key must be the name of the substitution variable.
[predicateFilter pushFilterWithSubstitutionValues:@{ @"searchTerm": @"an"}];

When a filter is pushed, the results are kept, so pushing another filter only searches through the already filtered objects.

If you've have pushed yourself too far, you can always pop a filter:

[predicateFilter popFilter];

There are many more ways to push and pop filters in CVPredicateFilter.h.

CVCompoundPredicateFilter

#import "CVCompoundPredicateFilter.h"

Segmented arrays can also be filtered. Perfect for those sectioned table views with searching.

CVCompoundPredicateFilter encapsulates several predicate filters and makes them appear as one regular CVPredicateFilter.

Like this:

NSArray *arrayOfArrays = @[@[@"one", @"two"], @[@"one", @"two"]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF BEGINSWITH $searchTerm"];

CVCompoundPredicateFilter *compoundFilter = [CVCompoundPredicateFilter compoundFilterWithSegmentedObjects:arrayOfArrays templatePredicate:predicate];

[compoundFilter pushFilterWithSubstitutionValues:@{ @"searchTerm": @"o" }];

NSLog(@"Filtered: %@", compoundFilter.filteredObjects); // Filtered: @[@[@"one"], @[@"one"]];

Note here that you would write the predicate exactly as you would for a single CVPredicateFilter.

Read more about NSPredicate here: NSPredicate programming guide NSHipster article

Credits

Distributed with an MIT License.

Contributions more than welcome.

Made by Kasper Timm Hansen. GitHub: @kaspth. Twitter: @kaspth.