PIP로 특정 버전 패키지 설치하는 법 To install a specific version of a package with pip

최신 버전의 패키지가 아니라 특정 버전의 패키지까지만 지원하는 경우 등 이미 설치된 최신 버전을 제거하고 지원가능한 특정 버전 설치는 다음과 같이 한다.

Use ==:

# pip install twisted==16.2.0
Collecting twisted==16.2.0
  Downloading Twisted-16.2.0.tar.bz2 (2.9MB)
    100% |████████████████████████████████| 2.9MB 100kB/s
Requirement already satisfied: zope.interface>=4.0.2 in /root/anaconda/envs/envalicia/lib/python3.5/site-packages (from twisted==16.2.0)
Requirement already satisfied: setuptools in /root/anaconda/envs/envalicia/lib/python3.5/site-packages/setuptools-23.0.0-py3.5.egg (from zope.interface>=4.0.2->twisted==16.2.0)
Building wheels for collected packages: twisted
  Running setup.py bdist_wheel for twisted ... done
  Stored in directory: /root/.cache/pip/wheels/fe/9d/3f/9f7b1c768889796c01929abb7cdfa2a9cdd32bae64eb7aa239
Successfully built twisted
Installing collected packages: twisted
Successfully installed twisted-16.2.0

설치된 버전 확인. 기존에는 17.1.0 버전이 설치되어 있었다.

# python
Python 3.5.2 |Anaconda custom (64-bit)| (default, Jul  2 2016, 17:53:06)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pip
>>> installed_packages = pip.get_installed_distributions()                                          
>>> installed_packages_list = sorted(["%s==%s" % (i.key, i.version) for i in pip.get_installed_distributions()])
>>> print(installed_packages_list)
[ 'twisted==16.2.0' ]
>>>