pip install pickle不工作-没有这样的文件或目录

Question

Ubuntu 16.04lts，试图用pip安装cpickle。我找了一下，还没找到有用的东西。

PYTHONPATH未设置。

错误消息

user@hostname:~$ sudo -H pip3 install cpickle
Collecting cpickle
  Using cached cpickle-0.5.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/usr/lib/python3.5/tokenize.py", line 454, in open
        buffer = _builtin_open(filename, 'rb')
    FileNotFoundError: [Errno 2] No such file or directory: '/tmp/pip-build-wn926hef/cpickle/setup.py'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-wn926hef/cpickle/
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.


    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-q46tq1l8/cpickle/
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

故障排除步骤

# version info
user@hostname:~$ python --version
Python 2.7.12
user@hostname:~$ python3 --version
Python 3.5.2

# I don't think cache is the problem
rm -rf ~/.cache/
sudo -H pip install  cpickle --no-cache-dir # same problem
sudo -H pip3 install  cpickle --no-cache-dir # same problem

Answer 1

在互联网上，我发现了这个

A common pattern in Python 2.x is to have one version of a module implemented in pure Python, with an optional accelerated version implemented as a C extension; for example, pickle and cPickle.

This places the burden of importing the accelerated version and falling back on the pure Python version on each user of these modules. In Python 3.0, the accelerated versions are considered implementation details of the pure Python versions.

Users should always import the standard version, which attempts to import the accelerated version and falls back to the pure Python version. The pickle / cPickle pair received this treatment. The profile module is on the list for 3.1. The StringIO module has been turned into a class in the io module.

也就是说在Python3中它是一个图书馆。。。

import _pickle as cPickle

Answer 2

cPickle是Python标准库的一部分；不能用pip安装它。在Python 2中，it comes installed with Python。在Python 3中，quoting the release notes添加了强调：

A common pattern in Python 2.x is to have one version of a module implemented in pure Python, with an optional accelerated version implemented as a C extension; for example, pickle and cPickle. This places the burden of importing the accelerated version and falling back on the pure Python version on each user of these modules. In Python 3.0, the accelerated versions are considered implementation details of the pure Python versions. Users should always import the standard version, which attempts to import the accelerated version and falls back to the pure Python version. The pickle / cPickle pair received this treatment.

在试图用pip安装cpickle的特定情况下，一些Pythonista决定通知人们这是错误的做法，因此注册了cpickle项目（以及许多以标准库模块命名的其他项目），并给了它一个setup.py，它只会退出并返回错误“Package 'cpickle' must not be downloaded from pypi”。但是，在创建包或PyPI端出现了错误，导致源分发文件格式不正确，从而导致此处出现错误。因此，即使这个错误被修正了，你仍然会得到一个不同的错误，告诉你不要做你想做的事情。