I tried a swift code that's working well in the playground but not in Xcode project. So I want to know how to change a Playground's particular swift version.
sorry but you can't apple documentation says playground only run on latest swift version on your xcode
Note: Swift Playgrounds 2.2 uses Swift 4.2 (swiftlang-1000.0.37.1). Code written using other versions of Swift may not work in Swift Playgrounds 2.2.
for more read this