-p py, --python py target interpreter for which to create a virtual (either absolute path or identifier string) 中 identifier string 的含义

$ virtualenv --help
-p py, --python py            target interpreter for which to create a virtual (either absolute path or identifier string) (default: /Library/Frameworks/Python.framework/Versions/3.6/bin/python3.6)

资料	网址
Use identifier string to set the target interpreter when creating virtualenv	https://github.com/pypa/virtualenv/issues/1819
官方对 identifier string 的说明	https://virtualenv.pypa.io/en/latest/user_guide.html#python-discovery