即使我尝试更新它，也无法更新 pip3

Question

综上所述，看来我进入一个循环，PIP认为我使用PIP的一个过时的版本，但是当我尝试升级它不容许我。所以我尝试安装（从这个问题Jupyter Notebook can't find modules for python 3.6）：

(automl) brandomiranda~ ? pip3 install ipykernel --upgrade
python3 -m ipykernel install --user
Requirement already up-to-date: ipykernel in /usr/local/lib/python3.6/site-packages (5.1.3)
Requirement not upgraded as not directly required: jupyter-client in /usr/local/lib/python3.6/site-packages (from ipykernel) (5.3.4)
Requirement not upgraded as not directly required: traitlets>=4.1.0 in /usr/local/lib/python3.6/site-packages (from ipykernel) (4.3.3)
Requirement not upgraded as not directly required: appnope; platform_system == "Darwin" in /usr/local/lib/python3.6/site-packages (from ipykernel) (0.1.0)
Requirement not upgraded as not directly required: tornado>=4.2 in /usr/local/lib/python3.6/site-packages (from ipykernel) (6.0.3)
Requirement not upgraded as not directly required: ipython>=5.0.0 in /usr/local/lib/python3.6/site-packages (from ipykernel) (7.11.1)
Requirement not upgraded as not directly required: jupyter-core>=4.6.0 in /usr/local/lib/python3.6/site-packages (from jupyter-client->ipykernel) (4.6.1)
Requirement not upgraded as not directly required: pyzmq>=13 in /usr/local/lib/python3.6/site-packages (from jupyter-client->ipykernel) (18.1.1)
Requirement not upgraded as not directly required: python-dateutil>=2.1 in /usr/local/lib/python3.6/site-packages (from jupyter-client->ipykernel) (2.8.1)
Requirement not upgraded as not directly required: six in /usr/local/lib/python3.6/site-packages (from traitlets>=4.1.0->ipykernel) (1.11.0)
Requirement not upgraded as not directly required: ipython-genutils in /usr/local/lib/python3.6/site-packages (from traitlets>=4.1.0->ipykernel) (0.2.0)
Requirement not upgraded as not directly required: decorator in /usr/local/lib/python3.6/site-packages (from traitlets>=4.1.0->ipykernel) (4.4.1)
Requirement not upgraded as not directly required: backcall in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (0.1.0)
Requirement not upgraded as not directly required: pickleshare in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (0.7.5)
Requirement not upgraded as not directly required: pexpect; sys_platform != "win32" in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (4.7.0)
Requirement not upgraded as not directly required: prompt-toolkit!=3.0.0,!=3.0.1,<3.1.0,>=2.0.0 in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (3.0.2)
Requirement not upgraded as not directly required: jedi>=0.10 in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (0.15.2)
Requirement not upgraded as not directly required: pygments in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (2.5.2)
Requirement not upgraded as not directly required: setuptools>=18.5 in /usr/local/lib/python3.6/site-packages (from ipython>=5.0.0->ipykernel) (39.0.1)
Requirement not upgraded as not directly required: ptyprocess>=0.5 in /usr/local/lib/python3.6/site-packages (from pexpect; sys_platform != "win32"->ipython>=5.0.0->ipykernel) (0.6.0)
Requirement not upgraded as not directly required: wcwidth in /usr/local/lib/python3.6/site-packages (from prompt-toolkit!=3.0.0,!=3.0.1,<3.1.0,>=2.0.0->ipython>=5.0.0->ipykernel) (0.1.8)
Requirement not upgraded as not directly required: parso>=0.5.2 in /usr/local/lib/python3.6/site-packages (from jedi>=0.10->ipython>=5.0.0->ipykernel) (0.5.2)
You are using pip version 10.0.1, however version 19.3.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Installed kernelspec python3 in /Users/brandomiranda/Library/Jupyter/kernels/python3

好的，我会升级，但它认为它已经升级了：

(automl) brandomiranda~ ? pip install --upgrade pip
Requirement already up-to-date: pip in ./miniconda3/envs/automl/lib/python3.7/site-packages (19.3.1)

但是当我再次尝试安装时，它失败并显示相同的消息。这似乎是一个鸡和蛋的问题。有谁知道这是怎么回事？

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过时：

我最近做了一个pip3 list检查我在我的虚拟环境中安装了哪些模块/项目，我得到了升级 pip 的建议。我试过了，但似乎无法更新/升级。我做了：

$ pip3 list
namespaces (4.2.0)
pip (8.0.2)
scikit-learn (0.18.1)
setuptools (19.4)
six (1.10.0)
wheel (0.26.0)
You are using pip version 8.0.2, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

所以我尝试这样做，它说它正在工作：

$ pip install --upgrade pip
Requirement already up-to-date: pip in /Users/user/home_simulation_research/hbf_tensorflow_code/venv/lib/python2.7/site-packages

因为它说它已经存在我再次做了 pip3 list 并且它一直说我实际上没有升级它。由于使用标准 pip 命令进行更新不起作用，因此我尝试使用pip3它进行更新，但仍然无效：

pip3 install --upgrade pip3
Collecting pip3
  Could not find a version that satisfies the requirement pip3 (from versions: )
No matching distribution found for pip3
You are using pip version 8.0.2, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

为什么不起作用？

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就在我认为它不起作用时，我尝试使用 pip3 升级 pip 和 pip3 升级 pip3。出于某种原因，后者似乎不起作用，但第一个起作用。即做：

$ pip3 install --upgrade pip

工作（或至少pip3 list）停止要求我升级。这是为什么？是我一个人还是这种行为真的很奇怪？

Answer 1

当您运行时pip3 list，您将列出为 python3 安装的软件包，而当您运行时pip install --upgrade pip，您正在检查 python2 软件包的更新。运行时pip3 install --upgrade pip3会报错，因为没有名为 pip3 的包，pip3 是 pip 包中提供的命令行工具。当您最终运行时pip3 install --upgrade pip，您正在做正确的事情（为 python3 安装更新，包名称是 pip）。