Azure Powershell to apply two tags (appId, environment) to all resources in the specified resource group

Apply-TagsToResourcesInRg.ps1

# Applies these two tags (appId, environment) to all resources in the specified resource group.
# Optional: resourcePattern will be used to select a subset of resources to apply tags to.
[CmdletBinding()]
param(
    [string] $resourceGroupName,
    [string] $appIdValue,
    [string] $environmentValue,
    [string] $resourcePattern = ""
)

$excludedResourceTypes = @("Microsoft.Compute/virtualMachines/extensions", "Microsoft.Compute/restorePointCollections")

$resources =  Get-AzureRmResource | Where-Object {$_.ResourceGroupName -eq $resourceGroupName} | Where-Object { $excludedResourceTypes -notcontains $_.ResourceType}

if ($resourcePattern -ne "")
{
    $resources = $resources | Where-Object { $_.Name -like $resourcePattern }
}


$resources | ForEach-Object {
    Write-Host ("Updating resource: " + $_.Name + " Type "+ $_.ResourceType)
    $isChanged = $false
    $tags = $_.Tags
    if ($tags -eq $null) 
    {
        $tags = @{}
    }
    
    if ($tags.ContainsKey("appIdOrProjectName"))
    {
        $isChanged = $tags["appIdOrProjectName"] -ne $appIdValue
    }
    else
    {
        $isChanged = $true
    }

    if ($tags.ContainsKey("environment"))
    {
        $isChanged = $isChanged -or ($tags["environment"] -ne $environmentValue)
    }
    else
    {
        $isChanged = $true
    }

    if (-not $isChanged) {
        Write-Host "No changed tags. Not updating."
    }
    else
    {
        $tags.Remove("appIdOrProjectName");
        $tags.Remove("environment");
        $tags += @{appIdOrProjectName = $appIdValue}
        $tags += @{environment = $environmentValue}
        Set-AzureRmResource -Tag $tags -ResourceId $_.ResourceId -Force
    }
}