在 python 中读取 YAML 配置文件并使用变量

2022-01-14 00:00:00 python config yaml

问题描述

假设我有一个 yaml 配置文件，例如:

Say I have a yaml config file such as:

test1:
    minVolt: -1
    maxVolt: 1
test2:
    curr: 5
    volt: 5

我可以使用以下方法将文件读入 python:

I can read the file into python using:

import yaml

with open("config.yaml", "r") as f:
    config = yaml.load(f)

然后我可以使用 

config['test1']['minVolt']

风格方面，使用配置文件中的变量的最佳方式是什么?我将在多个模块中使用变量.如果我只是简单地访问如上所示的变量，如果某些东西被重命名，我将需要重命名变量的每个实例.

Style-wise, what is the best way to use variables from the config file? I will be using the variables in multiple modules. If I simply access the variables as shown above, if something is renamed, I will need to rename every instance of the variable.

只是想知道在不同模块中使用配置文件中的变量的最佳或常见做法是什么.

Just wondering what the best or common practices for using variables from a config file in different modules.

解决方案

你可以这样做:

class Test1Class:
    def __init__(self, raw):
        self.minVolt = raw['minVolt']
        self.maxVolt = raw['maxVolt']

class Test2Class:
    def __init__(self, raw):
        self.curr = raw['curr']
        self.volt = raw['volt']

class Config:
    def __init__(self, raw):
        self.test1 = Test1Class(raw['test1'])
        self.test2 = Test2Class(raw['test2'])

config = Config(yaml.safe_load("""
test1:
    minVolt: -1
    maxVolt: 1
test2:
    curr: 5
    volt: 5
"""))

然后通过以下方式访问您的值:

And then access your values with:

config.test1.minVolt

重命名 YAML 文件中的值时，只需在一处更改类即可.

When you rename the values in the YAML file, you only need to change the classes at one place.

注意: PyYaml 还允许您直接将 YAML 反序列化为自定义类.但是，要使其正常工作，您需要向 YAML 文件添加标签，以便 PyYaml 知道要反序列化到哪些类.我希望您不想让 YAML 输入更复杂.

Note: PyYaml also allows you to directly deserialize YAML to custom classes. However, for that to work, you'd need to add tags to your YAML file so that PyYaml knows which classes to deserialize to. I expect that you do not want to make your YAML input more complex.

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