当默认点为pip2时,升级pip3的正确格式是什么？

Question

我为两者开发Python 2,3.
因此,我必须同时使用pip2和pip3.

使用时pip3 -我收到此升级请求(最后两行):

$ pip3 install arrow
Requirement already satisfied (use --upgrade to upgrade): arrow in c:\program files (x86)\python3.5.1\lib\site-packages
Requirement already satisfied (use --upgrade to upgrade): python-dateutil in c:\program files (x86)\python3.5.1\lib\site-packages (from arrow)
Requirement already satisfied (use --upgrade to upgrade): six>=1.5 in c:\program files (x86)\python3.5.1\lib\site-packages (from python-dateutil->arrow)
You are using pip version 7.1.2, however version 8.1.2 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

我的默认值pip是Python 2,:

$  python -m pip install --upgrade pip
Requirement already up-to-date: pip in /usr/lib/python2.7/site-packages

但是,以下任何显式命令都无法成功升级Python 3 pip:

$  python -m pip3 install --upgrade pip3
/bin/python: No module named pip3

$  python -m pip install --upgrade pip3
Collecting pip3
  Could not find a version that satisfies the requirement pip3 (from versions: )
No matching distribution found for pip3

$  python -m pip install --upgrade pip3.4
Collecting pip3.4
  Could not find a version that satisfies the requirement pip3.4 (from versions: )
No matching distribution found for pip3.4

当pip3不是默认的pip时,升级pip3的正确命令是什么？

环境:

$ python3 -V
Python 3.4.3
$ uname -a
CYGWIN_NT-6.1-WOW 2.5.2(0.297/5/3) 2016-06-23 14:27 i686 Cygwin

Answer 1

只需使用pip3您已有的命令:

pip3 install --upgrade pip

始终会调用已安装的项目pip.该pip3命令与Python 3安装相关联,并且是别名pip,但后者被pipPython 2安装程序中的命令所遮蔽.

你也可以使用相关的Python二进制文件来完成它; 如果它可执行python3,那么使用:

python3 -m pip install --upgrade pip

同样,调用项目pip,安装到site-packages目录中的模块也是如此,因此请坚持-m命令行选项和install命令的名称.