Snippets of Objective-C code handy for working with collections (Should go in a category, one day...)

CollectionSnippets.m

// Check if an item is in a NSMutableArray
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"pubDate = %@", tumblrPost.pubDate];
NSArray *filteredArray = [favoriteItems filteredArrayUsingPredicate:predicate];
if (filteredArray.count > 0) {
  // item found!
}

// Remove an item from a NSMutableArray 
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"createdAt = %@", facebookPost.createdAt];
[favoriteItems removeObjectsInArray:[favoriteItems filteredArrayUsingPredicate:predicate]];

// Sort a NSMutableArray with a NSComparisonResult
NSArray *sortedArray = [favoriteItems sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
  NSDate *firstCachedDate = [(RHCacheableBase *)a cachedDate];
  NSDate *secondCachedDate = [(RHCacheableBase *)b cachedDate];
  return [firstCachedDate compare:secondCachedDate];
}];

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