Relative access in a list

[fbhdr]

Is your feature request related to a problem? Please describe.
yaml file:

foo:
  bar: 3
  a: ${foo.bar}
  b: ${.bar}
  c: [2, "${foo.bar}"]
  d: [2, "${.bar}"]  # This line leads to an error

Python script:

conf = OmegaConf.load('debug.yaml')
OmegaConf.resolve(conf)

Then there is an error due to d: [2, "${.bar}"]:

omegaconf.errors.InterpolationResolutionError: TypeError raised while resolving interpolation: Index 'bar' (str) is not an int

Describe the solution you'd like
I want to use relative access in list, i.e. can use ${.bar} in a list [xxx, xxx, xxx].

[Jasha10]

Hi @fbhdr,
Please give the following a try:

foo:
  bar: 3
  a: ${foo.bar}
  b: ${.bar}
  c: [2, "${foo.bar}"]
  d: [2, "${..bar}"]

Using two dots in ${..bar} is necessary because the list counts as an additional level of nesting.

[loodvn]

Potentially related:
I have an index type error when I try relative interpolation within a list.

Steps to reproduce:

foo: bar

my_list:
  - y: "pre-${foo}-post"
    z: "pre-${..foo}-post"

conf = OmegaConf.load("example.yaml")
conf["list"][0]["y"]  # Returns "pre-bar-post"
conf["list"][0]["z"]  # Returns the following error:

Error:

File "/opt/conda/envs/benchmark/lib/python3.12/site-packages/omegaconf/omegaconf.py", line 1132, in _select_one
    raise TypeError(
omegaconf.errors.InterpolationResolutionError: TypeError raised while resolving interpolation: Index 'foo' (str) is not an int
    full_key: my_list[0].z
    object_type=dict

Let me know if I should open an issue. @Jasha10

[Jasha10]

@loodvn have you tried with three dots in the yaml file?
...z instead of ..z

[loodvn]

That solves it - thank you!