az-get-all-subnet.ps1

$dataFile = New-Item -Path $env:USERPROFILE -Name "azureVnet-$(get-date -Format ddMMyyyy-hhmmss).csv" -Force

$vnetInfoCollection = @()

Get-AzSubscription | Foreach-Object {

  $sub = Set-AzContext -SubscriptionId $_.SubscriptionId
  $vnets = Get-AzVirtualNetwork

  foreach ($vnet in $vnets) {

    $vnetInfo = [PSCustomObject]@{
        
      Subscription = $sub.Subscription.Name
      Name         = $vnet.Name
      Vnet         = $vnet.AddressSpace.AddressPrefixes
      Subnets      = $vnet.Subnets.AddressPrefix

    }

    $vnetInfoCollection += $vnetInfo

  }

}

$arrCountVnets = @()
$arrCountSubnets = @()

# Loop through each object and append count into the array
foreach ($object in $vnetInfoCollection) {

  $countVnet = $object.Vnet.Count
  $arrCountVnets += [int]$countVnet
  $countSubnet = $object.Subnets.Count
  $arrCountSubnets += [int]$countSubnet

}

# Get max value from array
$maxCountVnet = [int]($arrCountVnets | Measure -Maximum).Maximum
$maxCountSubnet = [int]($arrCountSubnets | Measure -Maximum).Maximum

# Loop through the result and get attribute inside each object
foreach ($object in $vnetInfoCollection) {

  $objVnet = [PSCustomObject]@{
    Subscription = $object.Subscription
    Name         = $object.Name

  }

  # create new object and append vnet into the objVnet
  for ($i = 0; $i -lt $maxCountVnet; $i++) {

    $keyName = "Vnet$($i)"

    $objVnet | Add-Member NoteProperty $keyName $object.Vnet[$i]

  }

  # create new object and append subnet into the objVnet
  if ($object.Subnets.Count -lt 2) {

    $keyName = "Subnet0"

    $objVnet | Add-Member NoteProperty $keyName $object.Subnets

  }
  else {

    for ($i = 0; $i -lt $maxCountSubnet; $i++) {

      $keyName = "Subnet$($i)"

      $objVnet | Add-Member NoteProperty $keyName $object.Subnets[$i]

    }

  }

  # output data to file and put some text on the console
  $objVnet | Export-Csv -Path $dataFile.FullName -Force -Append -NoTypeInformation

  Write-Output $objVnet 

}