更新pip版本 You are using pip version 18.1, however version 19.2.3 is available.

在安装selenium库时提示You are using pip version 18.1, however version 19.2.3 is available. You should consider upgrading via the ' python -m pip install --upgrade pip' command所以想着将pip更新到19.2.3版本
尝试python -m pip install　--upgrade pip和pip install --upgrade pip -vvv¹命令均不成功

尝试pip install --upgrade pip时，显示consider using the '--user' option or check the permissions²根据该提示将命令改为pip install --user --upgrade pip则提示Requirement already up-to-date: pip in c:\users\lu\appdata\local\programs\python\python37-32\lib\site-packages (19.2.3)，即是要求己经更新；

通过如下图pip --version命令可知pip确实已经更新成功；一定要通过 --version查看版本，因为出现过运行更新pip的命令后，提示要求己经更新，但实际上查看版本还是没更新成功的情况：

下图为该博客的整个尝试过程:

注：python版本为Python 3.7.2

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1. 成功解决：You are using pip version 10.0.1, however version 18.0 is available. ↩︎

2. consider using the ‘–user’ option or check the permissions错误 ↩︎