Couldn't find libpython

[randomjc]

Hi,

I get the following error when running Pkg.build("PyCall"):

===============================[ ERROR: PyCall ]================================

LoadError: Couldn't find libpython; check your PYTHON environment variable.

The python executable we tried was python (= version 2.7);
the library names we tried were ASCIIString["libpython2.7.so","libpython2.7","libpython"]
and the library paths we tried were UTF8String["/usr/lib","/usr/lib","/usr","/usr/lib"]
while loading /home/jc/.julia/v0.4/PyCall/deps/build.jl, in expression starting on line 13
================================================================================

================================[ BUILD ERRORS ]================================

WARNING: PyCall had build errors.

 - packages with build errors remain installed in /home/jc/.julia/v0.4
 - build the package(s) and all dependencies with `Pkg.build("PyCall")`
 - build a single package by running its `deps/build.jl` script

================================================================================

Here is my versioninfo():

Julia Version 0.4.5
Commit 2ac304d (2016-03-18 00:58 UTC)
Platform Info:
  System: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz
  WORD_SIZE: 64
  BLAS: libopenblas (NO_LAPACKE DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas
  LIBM: libopenlibm
  LLVM: libLLVM-3.8

I can see that there are files called libpython2.7.so.1 and libpython2.7.so.1.0 in /usr/lib and in /usr/lib/x86_64-linux-gnu, and libpython2.7.so in /usr/lib/python2.7/config-x86_64-linux-gnu. There is also some python3.5 directories and files lurking around, which does not sound like good installation. I don't know if my problem is related to a badly installed python, and if it's related to the problem discussed in #199. The last comment there suggests to set ENV["PYTHON"]="", but I have no idea how to do that. Any help would be greatly appreciated.

[stevengj]

Make sure you have the python2.7-dev package (or whatever it is called in your Linux distro) installed.

[randomjc]

That worked, thanks a lot! (Out of curiosity, was there an easy way for me to figure this out?)

[stevengj]

You can do a package search on the filename: https://packages.ubuntu.com/search?searchon=contents&keywords=libpython2.7.so&mode=exactfilename&suite=zesty&arch=any

(I'm surprised the -dev package wasn't installed by default on your system.)

[randomjc]

I see... Thanks again!