BloomFilter

public struct BloomFilter<T: BloomFilterType>

A Bloom filter is a probabilistic set designed to check rapidly and memory-efficiently, whether an element is definitely not in the set or may be in the set. The false positive probability is provided at construction time.

Inserted elements must conform to the BloomFilterType protocol. Types already conforming to the protocol include, but are not limited to: Int, Double and String.

Creating a BloomFilter

  • Creates a Bloom filter with the expected number of elements and a default false positive probability of 3%. Inserting significantly more elements than specified will result a deterioration of the false positive probability.

    Declaration

    Swift

    public init(expectedCount: Int)

  • Creates a Bloom filter with the expected number of elements and expected false positive probability. Inserting significantly more elements than specified will result in a deterioration of the false positive probability.

    Declaration

    Swift

    public init(expectedCount: Int, FPP: Double)

Querying a BloomFilter
  • FPP

    The expected false positive probability. In other words, the probability that contains() will erroneously return true.

    Declaration

    Swift

    public let FPP: Double

  • Returns the approximated number of elements in the bloom filter.

    Declaration

    Swift

    public var roughCount: Int

  • Returns true if no element has been inserted into the Bloom filter.

    Declaration

    Swift

    public var isEmpty: Bool

  • Returns true if the given element might be in the Bloom filter or false if it’s definitely not.

    Declaration

    Swift

    public func contains(_ element: T) -> Bool

Adding and Removing Elements

  • Inserts an element into the Bloom filter. All subsequent calls to contains() with the same element will return true.

    Declaration

    Swift

    public mutating func insert(_ element: T)

  • Removes all the elements from the Bloom filter.

    Declaration

    Swift

    public mutating func removeAll()