因為最近在做機器學習方面的學習，換了電腦之後python還沒有來得及安裝新模組

這次遇到的問題是

• 首先->需要安裝pip

⚠️-> python3 -m pip install -U pip

⚠️->是python3 （我的python版本是3.7，沒有刪除os自帶的2.7版本），若不標明則會安裝在系統預設路徑的版本里面

• 之後
  • 安裝matplotlib-> python3  -m pip install matplotlib
  • 安裝numpy -> python3 -m pip install numpy
• 安裝成功後
  • 輸入python3，進入python環境
  • import matplotlib(或者numpy)
  • 輸入-> matplotlib(或者numpy） 

juliadeMacBook-Pro:~ julia$ python3
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python37.zip', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload', '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages']
>>> import numpy
>>> numpy
<module 'numpy' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/numpy/__init__.py'>
>>> import matplotlib
>>> matplotlib
<module 'matplotlib' from '/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/matplotlib/__init__.py'>
>>> exit()