title: Python Modify OS Path Variable
body: <p>I am going to try and say this right but it's a bit outside my area of expertise.</p>
  
  <p>I am using the xgboost library in a windows environment with Python 2.7 which requires all kinds of nasty compiling and installation.  </p>
  
  <p>That done, the instructions I'm following tell me I need to modify the OS Path Variable in an iPython notebook before I actually import the library for use.</p>
  
  <p>The instructions tell me to run the following:</p>
  
  <pre><code>import os
  
  mingw_path = 'C:\\Program Files\\mingw-w64\\x86_64-5.3.0-posix-seh-rt_v4-rev0\\mingw64\\bin'
  
  os.environ['PATH'] = mingw_path + ';' + os.environ['PATH']
  </code></pre>
  
  <p>then I can import</p>
  
  <pre><code>import xgboost as xgb
  import numpy as np
  ....
  </code></pre>
  
  <p>This works.  My question.  Does the OS path modification make a <strong>permanent</strong> change in the path variable or do I need to modify the os path variable each time I want to use it as above?</p>
  
  <p>Thanks in advance.</p>
  
  <p>EDIT</p>
  
  <p>Here is a link to the <a href="https://www.ibm.com/developerworks/community/blogs/jfp/entry/Installing_XGBoost_For_Anaconda_on_Windows?lang=en" rel="nofollow noreferrer">instructions</a> I'm following.  The part I'm referencing is toward the end.</p>