我有以下YAML:
paths:
patha: /path/to/root/a
pathb: /path/to/root/b
pathc: /path/to/root/c
我如何“正常化”它,通过从三个路径中删除/path/到/root/,并将其作为自己的设置,类似于:
paths:
root: /path/to/root/
patha: *root* + a
pathb: *root* + b
pathc: *root* + c
显然这是无效的,我瞎编的。真正的语法是什么?这能做到吗?
是的,使用自定义标签。Python中的示例,使用!join标记连接数组中的字符串:
import yaml
## define custom tag handler
def join(loader, node):
seq = loader.construct_sequence(node)
return ''.join([str(i) for i in seq])
## register the tag handler
yaml.add_constructor('!join', join)
## using your sample data
yaml.load("""
paths:
root: &BASE /path/to/root/
patha: !join [*BASE, a]
pathb: !join [*BASE, b]
pathc: !join [*BASE, c]
""")
结果是:
{
'paths': {
'patha': '/path/to/root/a',
'pathb': '/path/to/root/b',
'pathc': '/path/to/root/c',
'root': '/path/to/root/'
}
}
join的参数数组可以包含任意数量的任何数据类型的元素,只要它们可以转换为字符串,因此!join [*a, "/", *b, "/", *c]就是您所期望的那样。
使用OmegaConf
OmegaConf是一个基于yaml的分层配置系统,在变量插值功能下支持此功能。使用OmegaConf v2.2.2:
创建YAML文件路径。Yaml如下:
paths:
root: /path/to/root/
patha: ${.root}a
pathb: ${.root}b
pathc: ${.root}c
然后我们可以读取可变路径的文件:
from omegaconf import OmegaConf
conf = OmegaConf.load("test_paths.yaml")
>>> conf.paths.root
'/path/to/root/'
>>> conf.paths.patha
'/path/to/root/a'
>>> conf.paths.pathb
'/path/to/root/b'
>>> conf.paths.pathc
'/path/to/root/c'
深度和交叉裁判
可以定义更复杂的(嵌套的)结构,使用变量的相对深度来引用其他变量:
创建另一个文件nested_paths.yaml:
data:
base: data
sub_dir_A:
name: a
# here we note that `base` is two levels above this variable
# hence we will use `..base` two dots but the `name` variable is
# at the same level hence a single dot `.name`
nested_dir: ${..base}/sub_dir/${.name}/last_dir
sub_dir_B:
# add another level of depth
- name: b
# due to another level of depth, we have to use three dots
# to access `base` variable as `...base`
nested_file: ${...base}/sub_dir/${.name}/dirs.txt
- name: c
# we can also make cross-references to other variables
cross_ref_dir: ${...sub_dir_A.nested_dir}/${.name}
我们可以再次检查:
conf = OmegaConf.load("nested_paths.yaml")
# 1-level of depth reference
>>> conf.data.sub_dir_A.nested_dir
'data/sub_dir/a/last_dir'
# 2-levels of depth reference
>>> conf.data.sub_dir_B[0].nested_file
'data/sub_dir/b/dirs.txt'
# cross-reference example
>>> conf.data.sub_dir_B[1].cross_ref_dir
'data/sub_dir/a/last_dir/c'
在无效引用的情况下(例如错误的深度,错误的变量名),OmegaConf将抛出错误OmegaConf .errors. interpolationresolutionerror。在Hydra中,它还用于配置复杂的应用程序。