numpy version creating issue. python 2.7 already installed
I just met the same problem. It's a issue about numpy preinstall in Python has a version number issue(required >=1.5, but found 1.8.0rc1).
Try running brew install python2 to upgrade your python which may solve this issue.
Getting few "package missing" errors while installing ipython on High Sierra.
matplotlib 1.3.1 has requirement numpy>=1.5, but you'll have numpy 1.8.0rc1 which is incompatible.