---
title: "appendInterpolation(standaloneWeekday:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/date/formatstring/stringinterpolation/appendinterpolation(standaloneweekday:)"
---

# appendInterpolation(standaloneWeekday:)

## Declaration

```swift
mutating func appendInterpolation(standaloneWeekday: Date.FormatStyle.Symbol.StandaloneWeekday)
```