如何查看pip安装包的所有版本；以及ipython的安装

安装ipython很简单，直接使用pip就行

比如mac环境下：pip install ipython；提示安装失败，原因是pip默认安装的ipython版本6.0+不适用python3.3以下版本

pip install ipython
Collecting ipython
  Downloading http://mirrors.aliyun.com/pypi/packages/fa/50/974211502bd72873728d44c3013fe79875c819c8fb69f778bcfd67bc7d38/ipython-6.2.1.tar.gz (5.1MB)
    % |████████████████████████████████| .1MB .6MB/s
    Complete output from command python setup.py egg_info:

    IPython 6.0+ does not support Python 2.6, 2.7, 3.0, 3.1, or 3.2.
    When using Python 2.7, please install IPython .x LTS Long Term Support version.
    Beginning with IPython 6.0, Python 3.3 and above is required.

    See IPython `README.rst` file for more information:

        https://github.com/ipython/ipython/blob/master/README.rst

    Python sys.version_info(major=, minor=, micro=, releaselevel='final', serial=) detected.

    ----------------------------------------
Command "python setup.py egg_info" failed with error code  in /private/var/folders/f2/cwy5vc4n4_v3q8qt7q09q1dh0000gn/T/pip-build-4fnKGC/ipython/
安装一个不存在的ipython版本5.xx,然后就会出现所有可以安装ipython版本

➜  ~ pip install ipython==.xx
Collecting ipython==.xx
  Could not find a version that satisfies the requirement ipython==.xx (from versions: 0.10, 0.10., 0.10., 0.11, 0.12, 0.12., 0.13, 0.13., 0.13., 1.0., 1.1., 1.2., 1.2., 2.0., 2.1., 2.2., 2.3., 2.3., 2.4., 2.4., 3.0., 3.1., 3.2., 3.2., 3.2., 3.2., 4.0.0b1, 4.0., 4.0., 4.0., 4.0., 4.1.0rc1, 4.1.0rc2, 4.1., 4.1., 4.1., 4.2., 4.2., 5.0.0b1, 5.0.0b2, 5.0.0b3, 5.0.0b4, 5.0.0rc1, 5.0., 5.1., 5.2., 5.2., 5.2., 5.3., 5.4., 5.4., 5.5., 6.0.0rc1, 6.0., 6.1., 6.2., 6.2.)
No matching distribution found for ipython==.xx

安装一个5.5.0版本

启动：ipython

参考：

1、http://ipython.org/install.html