How to iterate Azure pipelines parameter of type object

Question

I'm referring to this article, where the options of pipeline parameters are well described.

MS Learn: pipeline.parameters.parameter definition

This sample (I adapted it for my purpose) is contained but I miss a snippet on how to use it:

parameters:
- name: myObject
  type: object
  default:
    things0:
    - one
    - two
    - three
    things1:
    - four
    - five
    - six

I think about something like

- ${{ each element in parameters.myObject }}:
  - script: echo ${{ element }} # prints things0, things1
 
  - ${{ each subelement in element }}:
    - script: echo ${{ subelement }} # prints one, two, three resp. four, five, six

The requirement is basically to provide a two dimensional collection and being able to iterate over both levels. Maybe this can also be acheived elseway?

Answer 1

You can iterate over all the properties of a parameter like a dictionary (kind of), and access the key (property name) and corresponding value:

parameters:
  - name: myObject
    type: object
    default:
      things0:
      - one
      - two
      - three
      things1:
      - four
      - five
      - six

trigger: none

pool:
  vmImage: 'ubuntu-latest'

steps:
- ${{ each element in parameters.myObject }}:
  - script: echo ${{ element.key }}
    displayName: 'Echo ${{ element.key }}'
 
  - ${{ each subelement in element.value }}:
    - script: echo ${{ subelement }}
      displayName: 'Echo ${{ subelement }}'

Running the pipeline: