简单介绍python从yaml文件中读取变量的方法：

yaml文件的简单格式：

DESIGN:
    design_name:  chip
    flow_version: v0p1_5
    voltage:      
        1p8v
        3p3v

1、从以上的yaml文件中获取design_name,如果不为空的话，就打印出来；

2、获取voltage值，每个单独打印

示例如下：

import yaml

yaml_path = "design.yaml"

if os.path.exists(yaml_path):
    with open(yaml_path,'r') as f:
        yaml_data = yaml.load(f,Loader = yaml.FullLoader)
        if yaml_data['DESIGN']['design_name'] != None:
            print("design_name is " + yaml_data['DESIGN']['design_name'])
        else:
            print("design_name NOT EXIST!")
        if yaml_data['DESIGN']['voltage'] != None:
            for obj in yaml_data['DESIGN']['voltage']:
                print("voltage is " + obj)
        else:
            print("voltage NOT EXIST!")

输出结果：

design_name is chip
voltage is 1p8v
voltage is 3p3v