python 3 - vincios/rpi-setup GitHub Wiki

Overview

Apt's Python 3 version is always out-of-date, so we have to build it from scratch.

Install

Start by installing the packages necessary to build Python source

$ sudo apt update
$ sudo apt install build-essential tk-dev libncurses5-dev libncursesw5-dev libreadline6-dev libdb5.3-dev libgdbm-dev libsqlite3-dev libssl-dev libbz2-dev libexpat1-dev liblzma-dev zlib1g-dev libffi-dev

Download the latest release’s XZ compressed source tarball from the Python download page with wget or curl
```
$ wget https://www.python.org/ftp/python/3.X.Y/Python-3.X.Y.tar.xz
```
When the download is complete, extract the tarball, navigate to the Python source directory and run the configure script
```
$ tar -xf Python-3.X.Y.tar.xz
$ cd Python-3.X.Y
$ ./configure --enable-shared --enable-optimizations
```

[!NOTE] 💡 The script performs a number of checks to make sure all of the dependencies on your system are present. The --enable-optimizations option will optimize the Python binary by running multiple tests, which will make the build process slower

💡 The OPTIONAL --enable-shared option should be the equivalent of install the python-dev package from apt. python-dev contains the header files you need to build python extensions

Run make to start the build process
```
$ make -j 4
```

[!NOTE] 💡 Pass to the -j argument the number of cores in your CPU (4 for Raspberry Pi 4). You can check this with the command nproc

Once the build is done, install the Python binaries by running the following command as a user with sudo access
```
$ sudo make altinstall
```

[!CAUTION] ⚠️ Do not use the standard make install as it will overwrite the default system python3 binary

(OPTIONAL) If you have launched the command ./configure with the --enable-shared option, you must add the python shared libraries to the dynamic linker
```
$ sudo ldconfig -v /usr/local/lib 
```

[!TIP] 💡 Use the ldconfig utility is equivalent to add the /usr/local/lib path to the LD_LIBRARY_PATH environment variable. But the LD_LIBRARY_PATH environment variable should be set on each shell login (and is ignored by system services)

Clean up downloaded files

$ cd ..
$ sudo rm -rf Python-3.X.Y.tar.xz
$ sudo rm -rf Python-3.X.Y

Now Python 3 is installed. To use it instead of the system default you have to explicity run python3.X, such as

$ python3.X --version