ubuntu16.04下安装python3.7并设置默认调用版本

安装python3.7版本：

1. 下载源代码：

wget https://www.python.org/ftp/python/3.7.1/Python-3.7.1.tgz 

2. 解压缩：

 sudo tar -zxvf Python-3.7.1.tgz

3. 安装依赖

sudo apt-get install zlib1g-dev libbz2-dev libssl-dev libncurses5-dev libsqlite3-dev
sudo apt install libreadline-dev tk-dev libgdbm-dev libdb-dev libpcap-dev xz-utils libexpat1-dev
sudo apt install liblzma-dev libffi-dev libc6-dev

4. 编译

cd Python-3.7.1/
sudo  ./configure --prefix=/opt/python3.7
sudo make install

5. 创建连接（设置默认版本）

sudo ln -s /opt/python3.7/bin/python3.7 /usr/bin/python3

如果显示python3已存在，则删除原版本:

rm -rf /usr/bin/python3

6. 检查python版本

python3 -V

7. 安装pip

#下载源代码 ，如果连接失效就自行到官网下载。
wget https://files.pythonhosted.org/packages/b8/d3/155ebd29b6e34ac283614d3a1e7f476ffb93f535aa0d8b3647fa014815aa/setuptools-54.1.2.tar.gz
wget https://files.pythonhosted.org/packages/b7/2d/ad02de84a4c9fd3b1958dc9fb72764de1aa2605a9d7e943837be6ad82337/pip-21.0.1.tar.gz
#解压
sudo tar -zxvf setuptools-54.1.2.tar.gz
sudo tar -zxvf pip-21.0.1.tar.gz
#安装setuptools
cd setuptools-54.1.2
sudo python3 setup.py build
sudo python3 setup.py install
#安装pip
cd ..
cd pip-21.0.1
sudo python3 setup.py build
sudo python3 setup.py install
#连接（设置默认pip3)
sudo ln -s /opt/python3.7/bin/pip3.7 /usr/bin/pip3

安装完成！！