如何正确执行 Hydra 的 consolde 覆盖

Question

我有一个 yaml 文件

cars:
  - model: "Sedan"
    length: 4.5
    width: 1.8
    height: 1.4
    fuel_efficiency: 
    - 12  # City
    - 15  # Highway
    - 13  # Combined
  - model: "SUV"
    length: 4.8
    width: 2.0
    height: 1.7
    fuel_efficiency: 
    - 10
    - 12
    - 11
  - model: Hatchback
    length: 4.0
    width: 1.7
    height: 1.4
    fuel_efficiency:
    - 14
    - 18
    - 16

我使用 Hydra 编写了一个脚本，其中包含以下内容

import hydra
from omegaconf import DictConfig

@hydra.main(config_path="config", config_name="car_data", version_base=None)
def main(cfg:DictConfig):
    for car in cfg.cars:
        print(car.model)

我得到了值，做了一些计算，一切顺利！

我的问题是如何合并覆盖某些值（Hydra 的一项功能）

我已经尝试过了

>python process_cars.py cars[0].length=4.8
LexerNoViableAltException: cars[0].length=4.8
                               ^
See https://hydra.cc/docs/1.2/advanced/override_grammar/basic for details

我尝试阅读建议的文档，但无法弄清楚如何在这种情况下应用

Answer 1

问题在于 Hydra 的覆盖语法中访问列表元素的语法。对于列表，您需要使用点符号和数字，而不是方括号符号。以下是如何正确覆盖这些值：

python process_cars.py cars.0.length=4.8

针对您的配置的有效 Hydra 覆盖的更多示例：

# Change multiple properties of the first car
python process_cars.py cars.0.length=4.8 cars.0.width=2.0

# Change fuel efficiency values (since it's a nested list)
python process_cars.py cars.0.fuel_efficiency.0=13 cars.0.fuel_efficiency.1=16

# Change values for multiple cars
python process_cars.py cars.0.model=Coupe cars.1.height=1.8

# Change an entire fuel efficiency array
python process_cars.py cars.0.fuel_efficiency=[15,18,16]

至于覆盖 Hydra 中的整个数组，这里有几种方法：

# Method 1: Using square brackets
python process_cars.py cars.0.fuel_efficiency=[20,25,22]

# Method 2: If you prefer comma-separated without spaces
python process_cars.py cars.0.fuel_efficiency=[20\,25\,22]

您还可以将此与其他覆盖结合起来：

python process_cars.py cars.0.fuel_efficiency=[20,25,22] cars.0.length=4.8