title: ARM, how to make parameter file dependent on other parameter
body: <p>I'm trying to make my parameter file a bit smarter but for the life of me can't figure out how to do so. I have a parameters.json file with 2 params: env &amp; commonTags. env takes a string from my DevOps pipeline, and I need this parameter to fill a value in the commonTags-object parameter. See code snippet below:</p>
  <pre><code>{
  &quot;$schema&quot;: &quot;https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#&quot;,
  &quot;contentVersion&quot;: &quot;1.0.0.0&quot;,
  &quot;parameters&quot;: {
    &quot;env&quot;: {
    },
    &quot;location&quot;: {
      &quot;value&quot;: &quot;westeurope&quot;
    },
    &quot;commonTags&quot;: {
      &quot;value&quot;: {
          &quot;contact&quot;:&quot;dr@balloon.com&quot;,
          &quot;costcenter&quot;:       &quot;99999&quot;,
          &quot;env&quot;:              &quot;[parameters('env')]&quot;,
          &quot;criticality&quot;:      &quot;[parameters('env') == 'prd' ? 'high', 'low']&quot;
      }     
  }
  }
  </code></pre>
  <p>}</p>
  <p>The only other option I see is to set the env-specific parameters in the template file. Either by merging with the existing parameters or by setting the value of commonTags in the template file entirely. But I'd rather keep my template files free of parameter values and have these all located in a central parameter file.</p>
  <p>Can anybody point me in the right direction? I can't seem to find anything online.</p>
  <p>Many thanks!</p>