1.下载python3.9
    wget https://www.python.org/ftp/python/3.9.0/Python-3.9.0.tar.xz

    2.解压
    tar -xf Python-3.9.0.tar.xz

    3.进入目录
    cd Python-3.9.0

    4.安装依赖
    yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

    5.安装
    ./configure && make -j 4 && make install

    6.创建软链接
    ln -s /usr/local/src/Python-3.9.0/python /usr/bin/python
    你安装的python3.9的位置

    升级pip
    pip3 install —upgrade pip
    # 查看已安装的包
    pip3 freeze
    pip3 list
    # 检查哪些包需要更新
    pip3 list outdated