先看结论，直接使用即可，后续是过程

wget https://www.python.org/ftp/python/3.8.0/Python-3.8.0a2.tgz
tar -xvzf Python-3.8.0a2.tgz
cd Python-3.8.0a2
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get install libbz2-dev libncurses5-dev libgdbm-dev libgdbm-compat-dev liblzma-dev libsqlite3-dev libssl-dev openssl tk-dev uuid-dev libreadline-dev
sudo apt-get install libffi-dev
./configure --prefix=/usr/local/python3
make
sudo make install

切换版本

sudo update-alternatives --install /usr/bin/python python /usr/local/python3/bin/python3 1
sudo update-alternatives --install /usr/bin/pip pip /usr/local/python3/bin/pip3 1

sudo update-alternatives --config python
sudo update-alternatives --config pip

 

 

只是安装过程的记录

python3.8手动下载地址

https://www.python.org/ftp/python/3.8.0/

下载：

wget https://www.python.org/ftp/python/3.8.0/Python-3.8.0a2.tgz

由于在线下载太慢，我建议复制下载地址到迅雷等多线程下载工具里下载

https://www.python.org/ftp/python/3.8.0/Python-3.8.0a2.tgz

 

 

解压：

tar -xvzf Python-3.8.0a2.tgz
cd Python-3.8.0a2

配置：

./configure --prefix=/usr/local/python3

--prefix=/usr/local/python3：可选安装目录配置

尝试直接编译：

make

可在make后面加 -j4 其中4表示（CPU核心+线程数）数量，提供多线程编译。

例如我在虚拟里里分配了6个内核，使用make -j6

结果提示缺少了一些支持库

Python build finished successfully!
The necessary bits to build these optional modules were not found:
_bz2                  _curses               _curses_panel      
_dbm                  _gdbm                 _hashlib           
_lzma                 _sqlite3              _ssl               
_tkinter              _uuid                 readline           
zlib                                                           
To find the necessary bits, look in setup.py in detect_modules() for the modules name.

依次安装依赖库：

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get install libbz2-dev libncurses5-dev libgdbm-dev libgdbm-compat-dev liblzma-dev libsqlite3-dev libssl-dev openssl tk-dev uuid-dev libreadline-dev

再次执行配置和编译：

./configure --prefix=/usr/local/python3
make -j6

尝试安装：

sudo make install

 安装报错：

    from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
Makefile:1185: recipe for target 'install' failed
make: *** [install] Error 1

安装所需依赖库

sudo apt-get install libffi-dev

再次安装：

sudo make install

成功，安装目录为

/usr/local/python3

需要配置相应环境变量到安装目录才能直接使用命令行调用。