Azure devops pipeline, powershell split string, convert to json and assign to pipeline variable doesn't work - json

Question

I want to convert a pipeline variable - delimited string - to a json array and assign the json array to an other pipeline variable. See my code below, output stays empty. What am I missing here?
script:
steps:
- task: PowerShell#2
inputs:
targetType: inline
script: |
$test = "LZ-UK;LZ-ES;LZ-NL"
$json = $test.Split(";") | ConvertTo-Json -AsArray
Write-Host "##vso[task.setvariable variable=JsonLZ]$json"
Write-Host "Assigned the variable"
Write-Host "New `r`n $($JsonLZ)"
- script: |
echo ${{ variables.JsonLZ }}
output:
Starting: PowerShell
==============================================================================
Task : PowerShell
Description : Run a PowerShell script on Linux, macOS, or Windows
Version : 2.200.0
Author : Microsoft Corporation
Help : https://learn.microsoft.com/azure/devops/pipelines/tasks/utility/powershell
==============================================================================
Generating script.
========================== Starting Command Output ===========================
/usr/bin/pwsh -NoLogo -NoProfile -NonInteractive -Command . '/home/vsts/work/_temp/380b437f-74c4-4883-9d4a-7b4f3ac79266.ps1'
"LZ-UK",
"LZ-ES",
"LZ-NL"
]
Assigned the variable
New
Finishing: PowerShell

Answer 1

You're very close. There were a few minor issues that I spotted with your YAML/PowerShell:
You forgot the semicolon after the variable name in "##vso[task.setvariable variable=JsonLZ]$json", it should be: "##vso[task.setvariable variable=JsonLZ;]$json"
You should be using $(JsonLZ) instead of ${{ variables.JsonLZ }}. The former will be evaluated at runtime, the latter at compile-time. Here's a link to the MS Docs: Understand variable syntax
Give this a try to see a working example:
name: Stackoverflow-Example-Pipeline
trigger:
- none
variables:
JsonLZ: 'UNSET'
stages:
- stage: StageA
displayName: "Stage A"
jobs:
- job: example_job
displayName: "Example Job"
pool:
vmImage: "ubuntu-latest"
steps:
- task: PowerShell#2
inputs:
targetType: inline
script: |
$test = "LZ-UK;LZ-ES;LZ-NL"
$json = $test.Split(";") | ConvertTo-Json -Compress
Write-Host "##vso[task.setvariable variable=JsonLZ;]$json"
Write-Host "Assigned the variable"
- script: |
echo $(JsonLZ)
echo ${{ variables.JsonLZ }}