问无法通过MAC OS中的pip安装rpy2

EN

host-217:~ ChenGuanYing$ sudo pip install rpy2
The directory '/Users/ChenGuanYing/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/ChenGuanYing/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Collecting rpy2
  Downloading rpy2-2.7.8.tar.gz (178kB)
    100% |████████████████████████████████| 184kB 1.1MB/s 
    Complete output from command python setup.py egg_info:
    Error: Tried to guess R's HOME but no command (R) in the PATH.

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/tmp/pip-build-OtKzsd/rpy2/