As of Jan 2019, Raspberry Pi comes with Python 3 but it’s an older version of Python 3 (<3.6). The latest Python version is 3.7.2 at the time of this post. If we want to use the latest version on Raspberry Pi, we need to compile it from the source. Please make sure to note the use of ‘sudo’ in the command lines because at certain lines you don’t want to have sudo because it’ll change the location of the configuration and installation and you might not end up with a working Python 3.7.2

First make sure you update your Raspbian to the latest update. If any prompt comes up just answer ‘yes’. There might be some information page that you have to scroll through by holding down the space key to the end. After that press q to continue with the installation.

$ sudo apt-get update
$ sudo apt-get -y dist-upgrade

Your Raspberry Pi might require a reboot. If you end up with a black screen and no response at some point then you can unplug and plug in the power to re-start your Pi.

Now you are ready to upgrade to Python 3.7.2. One thing to note is that your GPIO libraries that’s specific to the hardware might not work. You can always still access your original system Python 3 using /usr/bin/python 3 to bring up the original system Python3

$ /usr/bin/python3

Before downloading and compiling the new Python 3, install all the required packages to do this:

$ sudo apt-get install libffi-dev libbz2-dev liblzma-dev libsqlite3-dev libncurses5-dev libgdbm-dev zlib1g-dev libreadline-dev libssl-dev tk-dev build-essential libncursesw5-dev libc6-dev openssl git

You might have to force install libssl-dev 1.0.2 in order to get pip to work with Python 3.7.2 since apparently you have to have OpenSSL 1.0.2 or 1.1 compatible libssl.

You can check your version of libssl-dev using this command:

$ sudo apt-cache policy libssl-dev

I found a post discussing how he solved this issue by running this install first before compiling Python 3.7.2

$ sudo apt install -t jessie-backports libssl-dev

Download Python 3.7.2 and extract it.

$ wget https://www.python.org/ftp/python/3.7.2/Python-3.7.2.tar.xz
$ tar xf Python-3.7.2.tar.xz
$ cd Python-3.7.2

Now configure the directory. It’s important to have the –with-ssl option or openssl wouldn’t be included. This will take a couple of minutes:

$ ./configure --prefix=$HOME/.local --with-ssl --enable-optimizations

Build and install Python 3.7.2. This step takes a long time. On my Raspberry Pi B (not B+) it takes about 30 minutes. DO NOT USE SUDO! Make sure to have the -l 4 option there to keep the error build limit or you’ll encounter problems.

$ make -j -l 4
$ make install

After the installation is done, update ~/.bashrc so that when you type Python3 as a command it will choose Python 3.7.2 over the pre-installed Python 3.4.

$ nano ~/.bashrc

Add the following line at the end of the file. Save and the exit nano.

export PATH=$HOME/.local/bin/:$PATH

You can now close this terminal and open a new one. Launch python3 using the following command and check what version you have. Use exit() to quit Python.

$ python3

You can also check what version of pip3 you have by typing in the command:

$ pip3 --version

Remember to have the 3 at the end of these commands otherwise you’ll launch the default Python 2.7.

If there you have limited space on your Raspberry Pi, you might want to remove all the compile tools and the source code to free up space. Use the following commands. Make sure you are not in the Python-3.7.2 directory where we were doing the compiling.

$ cd $home
$ sudo rm -r Python-3.7.2
$ sudo rm Python-3.7.2.tar.xz
$ sudo apt-get --purge remove libffi-dev libbz2-dev liblzma-dev libsqlite3-dev libncurses5-dev libgdbm-dev zlib1g-dev libreadline-dev libssl-dev tk-dev build-essential libncursesw5-dev libc6-dev openssl git -y
$ sudo apt-get autoremove -y
$ sudo apt-get clean

I want to give credit to the following pages for the original content on how to install Python 3.7.x on Raspbian:

https://gist.github.com/SeppPenner/6a5a30ebc8f79936fa136c524417761d
https://www.scivision.co/compile-install-python-beta-raspberry-pi/
https://medium.com/@dblume/getting-pip-working-for-python-3-7-on-rasbian-f414d9d526d0

Enjoy Python 3.7.2 on Raspberry Pi!

I have noticed in the recent weeks how pixelated all the texts in my Chrome Browser look. Take a look at Monoprice web page and see how all the texts are pixelated. Compare it to the same page rendered on *gasp* Internet Explorer (not Edge Explorer).

So why does it do this? I don’t know so I started looking for answers online. I went to several tech forums and posts and many suggested tweaking the settings on Chrome like font anti-aliasing. Noting worked for me until I stumbled upon a comment posted in one of those forums. I can’t remember where I found it now or I would give the author the credit he/she deserves.

To fix the problem I have, I go to:

chrome://flags

A warning that this is a settings page that Google doesn’t really want you to mess with unless you know what you are doing. So you probably don’t want to randomly set things. We are just going to just change the option “LCD text antialiasing”. You could search for it on the page by using Ctrl+F or Command + F on Mac.

On my Chrome, it’s set to “Enabled” so I’m just going to set it to “Disabled”. On a different computer, I see it as “Disabled” so I set it to “Enabled”. Basically just toggle the state of that option from whatever you have now to get rid of the text aliasing issue. You could also try setting it to “Default”. If that doesn’t work, you can come back to this page again and set to a different state that works for you.

Chrome will re-launch. If you have nice looking and pixelation free texts again, you are all set!

I just tried enabling WSL on a new Windows 10 computer today using the instructions I wrote in the post last year and found out that when you launch bash you no longer get to install Ubuntu automatically.

Now you need to download the install from Windows Store which I despise and it doesn’t even let me click the link. Luckily there’s a way around getting the install from Windows Store. You can download the install file directly from the providers of the distros. Click on the link of the distro you prefer. In my case, I picked Ubuntu 18.04.

• Ubuntu 18.04
• Ubuntu 18.04 ARM
• Ubuntu 16.04
• Debian GNU/Linux
• Kali Linux
• OpenSUSE
• SLES

Once you download the file, just launch it to get the setup going. There’s not much of an indication message during the install so wait a while and click Enter and it would ask for you UNIX username and password. After that the installation is done.

I believe there’s a way to install more than one distro but I’m not going to get into that in this post.

After you have Ubuntu installed, you can follow the previous post to get X-11 server for display output and Anaconda working on WSL.

Enjoy!

I posted about how to enable WSL on Windows 10 a while back.  At the time, the included Ubuntu Linux version would have been Ubuntu 14.04.5 LTS.  It’s been a while and WSL has matured to get to newer version.   Why upgrade to a newer version of Ubuntu?  So we can take advantage of new features offered such as using SciPy and other modules in Python. Other Linux distributions are now also supported in WSL but I’m not going to cover them in this post.

So let’s upgrade our Ubuntu to the latest version and then I’ll cover installing Xming Server so we can use graphical output needed for Matplotlib.  Yes, although not officially, we can now have graphical output in WSL through a 3rd party program which is a good start.

First, check to see what version of Ubuntu we have.  Enter the following command in WSL bash:
$ lsb_release -a
This should return the information on the Ubuntu version we have

Just for fun, we can also check what version of Windows we have using the following command:
$ cmd.exe /c "systeminfo" | grep "^OS Version"

Right here alone makes it worth while using WSL. Can’t do grep in command prompt but here we can.

Once we confirmed that we have the older version, let’s update to the latest version by typing in the following commands:
$ sudo -S apt-mark hold procps strace
$ sudo -S env RELEASE_UPGRADER_NO_SCREEN=1 do-release-upgrade

This will go through a bunch of fetching and about a couple of minutes in it’ll prompt you to continue with the installation since this will take a couple of hours. After all we are replacing the entire Ubuntu version here. Type in Y to continue and now let it run for a while. There might be several more prompts later so don’t go away and expect it to be done when you get back.

At the end, you’ll need to reboot WSL. With the newer version of WSL, closing the bash window won’t stop all the services. You can manually stop and restart WSL using command prompt (with Administrative Rights). Close the Bash window and then Run command prompt as Administrator and then type in the following commands:

net stop LxssManager
net start LxssManager

Relaunch WSL and check your Ubuntu version again.  At the time of this post, I have 16.04.5 LTS (xenial) using this method.  I guess that it doesn’t jump right from 14.04 to 18.08 in one upgrade. I do know that 18.08 version is available so we need to do more to update to the latest version.  We’ll do the following commands to bring 16.04 up-to-date:

$ sudo apt update -y # makes apt system up-to-date
$ sudo apt upgrade -y # upgrades/makes up-to-date current Ubuntu 16.04 packages

Now we do another update to make sure everything is good and then do another release upgrade.

$ sudo apt update && sudo apt -y upgrade

If more packages are found and need to be upgraded then you need to do it or it won’t let you upgrade to the next release. While I was doing this, there were 2 packages that could be upgraded but didn’t because they were kept back for some reasons. You can install them manually using:

$ sudo apt-get install

In my case, I hade procps and sudo packages that need to be install. I think it’s maybe because I made some modification to them in the previous version and I did ask the installer to keep my local configurations from before. Maybe it would been better to just install fresh config when I did the upgrade. Once the installs are done, try running the update again to see if there’s anything left to upgrade.

Once you have nothing to update/upgrade, it’s time to get to the next version 18.04.

$ sudo do-release-upgrade

Again this will take a while. We’ll have to do the same process as before and then check the version again. Once we have 18.04, we are done! (for now until the next release).

Installing Xming X11 Server:
Head over to Source Forge and install Xming to allow graphical output for WSL.
After the installation is done, modify the system configuration file using the following command:
$ sudo nano ~/.bashrc
Add at the bottom of the file the following lines

export DISPLAY=localhost:0.0 

Windows firewall might pop up here. Choose to only allow local traffic and block it from going outside since the X-server runs locally and there’s no need to have it be exposed to the outside world for security precautions. Set the scope to just your local IP 127.0.0.1

Launch X-server and have it run in the background.  You should see a little icon for Xming in the running program icon box.  Try installing some X-11 programs using the following command:

$ sudo apt-get install x11-apps

Now run a sample program like Xcalc:

$ xcalc

You should see a calculator program showing up on your desktop. You can move it around just as you do as a normal windows program!

If you have an error with “no display output”, check that the firewall is correctly enabled for the local host connection. You can also make sure that the display is correctly set up by sending this command:

$ export DISPLAY=localhost:0.0

Installing Anaconda:
Now that we have the graphical output, we are ready to use Matplotlib, but trying to manually install all the dependencies is quite annoying to deal with. Therefore, we’ll install a python package like Anaconda so that we get everything we need for python using the “conda” command. Since this is 2019, let’s use Python 3.x. I think it’s about time to move on to the new version since I have been stuck using 2.x for the last decade.

First, install Anaconda with wget. Let it sift through all the servers until it finds what it needs. Might take a while so sit back and relax.

$ sudo wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh

After the it found the package it needs, execute the installation:

$ bash Miniconda3*.sh

Just watch the installation process and at some point you’ll have to supply a Y to proceed with the installation.

Now run the following lines to update Qt 5 and get the latest configuration of Anaconda to prevent errors with Qt5.6 WebKitEngine error that people get if they want to launch Spyder IDE.

sudo apt-get install python-pyqt5.qtwebkit

After this is done, you should be able to launch Spyder IDE with Spyder command, but let’s wait until we install all the great packages to use in Anaconda first. Get all the packages we need for data science:

$ conda install numpy pandas scipy matplotlib seaborn scikit-learn

After the installation is done, now you can launch Spyder IDE:

$ spyder


If you run into problems with the ModuleNotFoundError: No module named ‘PyQt5.QtWebKitWidgets’, run this command (*Warning: this will break MatPlotlib! There’s no solution at the moment because the newest Matplotlib uses the new Qt 5.9 but this causes problem with Spyder):

conda update qt pyqt -c conda-forge

After the installation is done, it should fix the problem. Try launching Spyder IDE again and you should now have the program on your desktop.

One thing to note is that sometimes after you exit Spyder IDE, the program might still be there and you can no longer launch it again. To kill it, just exit X-server by Right clicking the X-server icon in the Icon Tray and click Exit. It will give you a warning about terminating all the program running on X-server. This will terminate Spyder display running on X-server. Close out the bash window and use command prompt to stop and re-start the service so that we don’t have any more programs running in the background.

Start X-server first and then the bash window again. You can also check to make sure that there’s no more file associated with Spyder:

$ cd ~/.spyder
or

$ cd ~/.spyder-py3

If this does exist, the remove the lock by using this command:

$ rm -f spyder.lock

Now you should be able to start Spyder again. Let’s try running MatPlotLib to make sure that this works. Let’s use this example code

import matplotlib.pyplot as plt
import numpy as np


def f(t):
    'A damped exponential'
    s1 = np.cos(2 * np.pi * t)
    e1 = np.exp(-t)
    return s1 * e1


t1 = np.arange(0.0, 5.0, .2)

l = plt.plot(t1, f(t1), 'ro')
plt.setp(l, markersize=30)
plt.setp(l, markerfacecolor='C0')

plt.show()

Unfortunately, looks like our MatPlotlib is now broken because the update Qt command we ran. We can reinstall MatPlotlib, but then it breaks the Qt again because of the update from Qt 5.6 to Qt 5.9. At the moment I don’t have a solution to this. Maybe Spyder will get updated to fix this issue with the new Qt problem. In the mean time, you can re-install Matplotlib and should be able to execute the code to generate a plot via X-11 output.

That’s it for now. Enjoy coding!