Error "Not a valid number. Expecting a whole number between 1-0" shows when running xcodes select when no Xcode is installed

[ngimelliUW]

Summary
If you try to run xcodes select when no version of Xcode is installed, you get the error:

Not a valid number. Expecting a whole number between 1-0, but given...

This can possibly happen if an installation of a new Xcode version partially completes (uninstalling previous versions), but does not finish installing the new version. A user under the false impression that a new Xcode version is installed might then run this command, and the error message does not make sense.

Screenshots

Proposed Solution
If no Xcode version is installed, it should say Xcode is not installed. Please run 'xcode install' to install a version.