在Ubuntu系统中更新Python，可以通过以下几种方法：

1、使用官方PPA源

打开终端，输入以下命令添加官方PPA源：

sudo addaptrepository ppa:deadsnakes/ppa

更新软件包列表：

sudo aptget update

接下来，安装指定版本的Python，例如安装Python 3.8：

sudo aptget install python3.8

检查Python版本是否已经更新：

python3.8 version

2、使用pyenv管理多个Python版本

安装pyenv：

sudo aptget update
sudo aptget install y make buildessential libssldev zlib1gdev libbz2dev 
libreadlinedev libsqlite3dev wget curl llvm libncurses5dev libncursesw5dev 
xzutils tkdev libffidev liblzmadev pythonopenssl git
curl https://pyenv.run | bash

接下来，配置环境变量：

echo 'export PATH="~/.pyenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init )"' >> ~/.bashrc
source ~/.bashrc

安装指定版本的Python，例如安装Python 3.8：

pyenv install 3.8.0

接下来，设置全局Python版本为刚刚安装的版本：

pyenv global 3.8.0

检查Python版本是否已经更新：

python version

3、使用pip升级Python包

确保已经安装了pip：

sudo aptget install python3pip

升级pip到最新版本：

pip3 install upgrade pip

接下来，升级Python的第三方库：

pip3 list outdated | cut d " " f 1 | xargs n 1 pip3 install U

检查Python版本以及第三方库是否已经更新：

python3 version && pip3 list outdated | grep v "^(Requirement already uptodate|Could not find a version that satisfies the requirement)" && echo "Python and thirdparty libraries are updated." || echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit 1; echo "Update failed." && exit 1; echo "Python and thirdparty libraries are updated." || exit