I tried using the Python library from Ruby with PyCall

• The latest version has been released.

The library has been updated and the usage has changed considerably. Please check the article below for a description of the new version.

[Use PyCall to defeat Python libraries from Ruby] (https://qiita.com/mix_dvd/items/d49ed4ff6553f3ace5a7)

Introduction

mrkn has developed a library called PyCall, so I tried it immediately.

https://twitter.com/mrkn

Installation

As of February 24, 2017, you can install it by following the steps below. Thank you, mrkn.

python

gem install --pre pycall

Old installation method

I will leave it as a memorandum. If you cannot install by the above procedure, please try it.

You can download the source code from GitHub.

https://github.com/mrkn/pycall

As of February 23, 2017, it was said that it will be downloaded from the branch under development, so I got it with the following command.

python

git clone -b eval https://github.com/mrkn/pycall.git

From there, I had a little trouble installing Gem, but I was able to install it by following the steps below. If anyone knows a smarter way, please let me know (sweat)

python

#Creating a Gem file
gem build pycall/pycall.gemspec 
#Install Gem
gem install pycall-0.1.0.alpha.gem 
#For some reason, the Gem folder is empty, so delete it for the time being
rm -rf ~/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/pycall-0.1.0.alpha
#Copy the downloaded source
mv pycall ~/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/pycall-0.1.0.alpha

By the way, I installed Python with Anaconda and used it, and Ruby installed it with rbenv.

Try drawing a graph for the time being

I was able to display the graph with the following code.

python

require 'pycall/import'
include PyCall::Import

pyimport 'numpy', as: 'np'
pyimport 'matplotlib.mlab', as: 'mlab'
pyimport 'matplotlib.pyplot', as: 'plt'

plt.plot.([1,3,4,6,7,9])
plt.plot.([3,2,4,1,5,0])
plt.show.()

Try to display the graph in iRuby Notebook

When I run the above source code in iRuby Notebook, I can draw the graph, but the graph is displayed in a separate window as well.

Moreover, the subsequent operation is a little unstable (sweat)

This is a bit of a problem, so change it as follows.

python

require 'pycall/import'
include PyCall::Import

pyimport 'numpy', as: 'np'
pyimport 'matplotlib.mlab', as: 'mlab'
pyimport 'matplotlib.pyplot', as: 'plt'

plt.plot.([1,3,4,6,7,9])
plt.plot.([3,2,4,1,5,0])

#Save the graph as an image
plt.savefig.("pycall.png ")
plt.close.()

#Load the saved graph image
open("pycall.png ")

I was able to display it inline.

Try resizing the graph

If you don't specify it, a square graph will be displayed, so change it a little.

python

require 'pycall/import'
include PyCall::Import

pyimport 'numpy', as: 'np'
pyimport 'matplotlib.mlab', as: 'mlab'
pyimport 'matplotlib.pyplot', as: 'plt'

plt.figure.(figsize: PyCall.tuple(8, 3))
plt.plot.([1,3,4,6,7,9])
plt.plot.([3,2,4,1,5,0])

#Save the graph as an image
plt.savefig.("pycall.png ")
plt.close.()

#Load the saved graph image
open("pycall.png ")

did it!

Next time you want to try machine learning (^-^)

I also tried machine learning (additional note)

You can refer to the result of executing the power demand forecast from the following URL, so please have a look if you are interested.

Power demand forecast from actual power demand http://blueomega.jp/predict_kw_with_pycall.html

Power demand forecast by adding the temperature one hour ago to the actual power demand http://blueomega.jp/predict_kw_with_temp_and_pycall.html