ArcGIS for Desktop geoprocessing tools require that Python 2.7.5 and Numerical Python 1.7.1 are installed. Additionally, matplotlib 1.3.0, xlrd 0.9.2, xlwt 0.7.5, and Pyparsing 1.5.7 are also installed. If the ArcGIS for Desktop setup does not find either Python 2.7.5 or Numerical Python 1.7.1 (NumPy) installed on the target computer, Python and all required components will be installed during a complete installation. You can choose a Custom installation to unselect the Python feature and avoid installing it. Additionally, if Python is installed during the ArcGIS for Desktop installation, you will be provided with the opportunity to choose its installation location. The Python installation location should not include spaces.
Uninstalling Python
When Python, NumPy, and their components are installed by the ArcGIS for Desktop setup, they are also uninstalled when you remove ArcGIS for Desktop. You can manually install Python 2.7.5, NumPy 1.7.1, and matplotlib and the other resources prior to installing ArcGIS for Desktop. If Python and NumPy are both found by the ArcGIS for Desktop setup program, Python components will not be installed and, as a result, will not be uninstalled.
3/7/2014