Common usage
pip uninstall command library
python unstall filename
pip update command
python -m pip install --upgrade pip
pip modify the file the default installation path
python -m site
First, we will find the above command, pip default installation path is as follows 
, but personally do not like because there are too many files in the system tray, so I want to change the default download location, so I took a turn in this command .
python -m site -help
Here I know, his profile is site.py, I only need to modify his configuration on it.
# Prefixes for site-packages; add additional prefixes like /usr/local here
PREFIXES = [sys.prefix, sys.exec_prefix]
# Enable per user site-packages directory
# set it to False to disable the feature or True to force the feature
ENABLE_USER_SITE = None
# for distutils.commands.install
# These values are initialized by the getuserbase() and getusersitepackages()
# functions, through the main() function when Python starts.
USER_SITE = None
USER_BASE = None
Where we will need to revise
USER_SITE = "D:\python\Python37\Lib\site-packages"
USER_BASE = "D:\python"
After saving we'll call the next command above
python -m site
This time we will find that the default path has been modified.
Then after I downloaded the library when you use the following command
python -m pip install -U flask --user
It will have a warning out, but is negligible, the file has entered a new path and download a success!
