升级到 Ubuntu 20.04 杀死了 pip

我从 19.10 升级到 Ubuntu 20.04，现在无法使用 pip。

zeno:~$ pip --version

Command 'pip' not found, but there are 18 similar ones.

Python已安装：

zeno:~$ python3 --version
Python 3.8.2

但如果我尝试安装 pip，我会得到以下信息：

    zeno:~/Desktop/tetris$ sudo apt install python3-pip
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    python3-pip is already the newest version (20.0.2-5ubuntu1).
    The following packages were automatically installed and are no longer required:
     dh-python elpa-async enchant gedit-plugin-zeitgeist gir1.2-mutter-5
     gnome-software-common libappstream-glib8 libapt-pkg5.90
     libboost-date-time1.67.0 libboost-iostreams1.67.0 libbrlapi0.6
     libcodec2-0.8.1 libcroco3 libdns-export1104 libdns1104 libdvdread4
     libegl1-mesa libenchant1c2a libept1.5.90 libevent-2.1-6 libexiv2-14
     libfprint0 libgeoip1 libgit2-27 libglvnd-core-dev libgnome-desktop-3-18
     libgspell-1-1 libgutenprint-common libgutenprint9 libgweather-3-15 libicu63
     libiptc0 libisc-export1100 libisc1100 libisc1105 libisl21 liblivemedia64
     liblouis17 liblwres161 libmicrodns0 libmozjs-60-0 libmutter-5-0 libmysofa0
     libnettle6 liboauth0 libperl5.28 libplymouth4 libpoppler90
     libpython3.7-minimal libqpdf21 libsnmp30 libusbmuxd4 libx11-xcb-dev
     libx265-176 libxcb-dri2-0-dev libxcb-dri3-dev libxcb-shape0-dev
     libxcb-sync-dev libxcb-xfixes0-dev libxshmfence-dev libzeitgeist-2.0-0
     perl-modules-5.28 printer-driver-gutenprint python-gobject-2
     python3-asn1crypto python3-pypdf2 python3.7-minimal ubuntu-system-service
     x11proto-composite-dev x11proto-fixes-dev
   Use 'sudo apt autoremove' to remove them.
   0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

我搞不清楚了。谢谢你的帮助

Update

我使用 venv 创建虚拟环境。当没有激活​​ venv 时，我可以使用 pip3：

zeno:~/Desktop/tetris$ pip3 -V
pip 20.0.2 from /usr/lib/python3/dist-packages/pip (python 3.8)

但如果我激活 venv，它就不起作用：

(.tetris) zeno:~/Desktop/tetris$ pip3
Traceback (most recent call last):
  File "/home/zeno/Desktop/tetris/.tetris/bin/pip3", line 6, in <module>
    from pip._internal import main
ModuleNotFoundError: No module named 'pip'

感谢您的建议和持续的帮助。

Update

我尝试删除 venv 并创建一个新的，但似乎我需要 pip 工作才能做到这一点：

zeno:~/Desktop/tetris$ python3 -m venv .tetris

gives:

The virtual environment was not created successfully because ensurepip is not
available.  On Debian/Ubuntu systems, you need to install the python3-venv
package using the following command.

    apt-get install python3-venv

You may need to use sudo with that command.  After installing the python3-venv
package, recreate your virtual environment.

Failing command: ['/home/zeno/Desktop/tetris/.tetris/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']

有时，操作系统升级后您需要重新安装软件包。尝试：

sudo apt install --reinstall python3-pip