# KeyedDecodingContainerProtocol Implementations ## Topics ### Instance Methods [`func decode(UInt128.Type, forKey: Self.Key) throws -> UInt128`](/documentation/Swift/KeyedDecodingContainer/decode(_:forKey:)-6bqbj) Decodes a value of the given type for the given key. [`func decode(Int128.Type, forKey: Self.Key) throws -> Int128`](/documentation/Swift/KeyedDecodingContainer/decode(_:forKey:)-6xvk4) Decodes a value of the given type for the given key. [`func decodeIfPresent(UInt64.Type, forKey: Self.Key) throws -> UInt64?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-339qj) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(UInt32.Type, forKey: Self.Key) throws -> UInt32?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-38d4y) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(T.Type, forKey: Self.Key) throws -> T?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-3pauu) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Float.Type, forKey: Self.Key) throws -> Float?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-3zl8i) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int.Type, forKey: Self.Key) throws -> Int?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-41lzh) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int8.Type, forKey: Self.Key) throws -> Int8?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-44yee) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(UInt8.Type, forKey: Self.Key) throws -> UInt8?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-4u87t) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int128.Type, forKey: Self.Key) throws -> Int128?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-4xmf7) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int32.Type, forKey: Self.Key) throws -> Int32?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-61cfc) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int64.Type, forKey: Self.Key) throws -> Int64?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-7rtzq) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(UInt.Type, forKey: Self.Key) throws -> UInt?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-7vy3k) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(UInt128.Type, forKey: Self.Key) throws -> UInt128?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-85hpp) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(UInt16.Type, forKey: Self.Key) throws -> UInt16?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-9fv11) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Double.Type, forKey: Self.Key) throws -> Double?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-9jeei) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Int16.Type, forKey: Self.Key) throws -> Int16?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-9tfza) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(Bool.Type, forKey: Self.Key) throws -> Bool?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-9ujt) Decodes a value of the given type for the given key, if present. [`func decodeIfPresent(String.Type, forKey: Self.Key) throws -> String?`](/documentation/Swift/KeyedDecodingContainer/decodeIfPresent(_:forKey:)-w7f) Decodes a value of the given type for the given key, if present. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)