python 3.8 新特性

安装 python 3.8 环境 , 在此刻 似乎 anaconda 都还不支持 3.8 ,所以直接下载源码进行编译安装

环境:  centos7.5

版本：python3.8

 

1、依赖包安装

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 libffi-devel



2、下载包：

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

wget https://www.python.org/ftp/python/3.8.0/Python-3.8.0a1.tgz


3、解压：
tar -zxvf Python-3.8.0.tgz


4、安装：

cd Python-3.8.0
./configure --prefix=/usr/local/python3
make && make install

5、建立软连接

ln -s /usr/local/python3/bin/python3.8 /usr/bin/python3
ln -s /usr/local/python3/bin/pip3.8 /usr/bin/pip3

6、测试一下python3是否可以用

python3
pip3

赋值表达式

>>> with open('py38_test.txt','r') as fr:
...     while (line:=fr.readline()) != 'efg':
...         print(line)
... 
abc

关键参数

f-string 用来 字符串调试输出

>>> x=2
>>> print(f'{x**3}')