# KeyedEncodingContainerProtocol Implementations ## Topics ### Instance Methods [`func encode(Int128, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encode(_:forKey:)-8yufz) Encodes the given value for the given key. [`func encode(UInt128, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encode(_:forKey:)-vjhq) Encodes the given value for the given key. [`func encodeConditional(T, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeConditional(_:forKey:)-2sxc0) Encodes a reference to the given object only if it is encoded unconditionally elsewhere in the payload (previously, or in the future). [`func encodeIfPresent(UInt16?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-1nn49) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Double?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-29g6g) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(UInt128?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-2bjaq) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int32?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-3afe0) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(T?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-3xv7m) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int16?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-46r8i) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Bool?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-4p0ik) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int8?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-4ws6m) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(UInt64?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-6cvd3) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(String?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-706xw) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(UInt32?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-7m9z7) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-809zp) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int128?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-836ib) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Float?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-954rq) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(UInt?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-e1h9) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(UInt8?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-n83l) Encodes the given value for the given key if it is not `nil`. [`func encodeIfPresent(Int64?, forKey: Self.Key) throws`](/documentation/Swift/KeyedEncodingContainer/encodeIfPresent(_:forKey:)-nej2) Encodes the given value for the given key if it is not `nil`. --- 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)