Conda cannot install pydot-ng with python3 (Unsatisfiable error)

Question

I have Anaconda 4.3.23 on Ubuntu 16.04 LTS. When I try to install pydot-ng package using

conda install pydot-ng

I get the following error:

UnsatisfiableError: The following specifications were found to be in conflict:
- pydot-ng -> python 2.7* -> openssl 1.0.1*
- python 3.6*
Use "conda info <package>" to see the dependencies for each package.

Upon running conda info pydot-ng i see

pydot-ng 1.0.0.15 py27_0
------------------------
file name   : pydot-ng-1.0.0.15-py27_0.tar.bz2
name        : pydot-ng
version     : 1.0.0.15
build string: py27_0
build number: 0
channel     : defaults
size        : 45 KB
arch        : x86_64
date        : 2015-09-09
license     : MIT
md5         : 8b81a344723e64ec3545b5f030caca47
noarch      : None
platform    : linux
url         : https://repo.continuum.io/pkgs/free/linux-64/pydot-ng-
1.0.0.15-py27_0.tar.bz2
dependencies:
   pyparsing
   python 2.7*

pydot-ng 1.0.0.15 py34_0
------------------------
file name   : pydot-ng-1.0.0.15-py34_0.tar.bz2
name        : pydot-ng
version     : 1.0.0.15
build string: py34_0
build number: 0
channel     : defaults
size        : 46 KB
arch        : x86_64
date        : 2015-09-09
license     : MIT
md5         : 13e3a10b45edfb38d91a51d6b3ccabc7
noarch      : None
platform    : linux
url         : https://repo.continuum.io/pkgs/free/linux-64/pydot-ng-
1.0.0.15-py34_0.tar.bz2
dependencies:
   pyparsing
   python 3.4*

What is the problem? Shouldn't conda be able to install the pydot-ng 1.0.0.15 py34_0 version which would be compatible with python 3.6 (I presume)?

Answer 1

That's not how conda works - the package is built for a specific version of Python, unless the package builder specifically says that its a universal package and can be installed for many versions. The simplest solution to this is to create a new environment to install this package:

conda create -n pydotng python=3.4 pydot-ng