For loop for Array in Powershell

Question

I have sample code as below:

$IP=@("IP1","IP2","IP3", "IP4" , "IP5")
$Hostname=@("Host1","Host2","Host3","HOST4", "HOST5")

$data = Read-Host -Prompt 'Please enter the data.'

if ($data -match 'zone1') {
    $Unity=$IP[0]
    $show=$hostname[0]
} elseif ($data -match 'site2'){
    $Unity=$IP[1]
    $show=$hostname[1]
} elseif ($data -match 'unit5'){
    $Unity=$IP[2]
    $show=$hostname[2]
} elseif ($data -match 'ALL DC'){
    $Unity=$IP
    $show=$hostname
}



foreach ($u in $Unity){

  echo "This is my IP" $u
  echo "This is my hostname" $show

}

Codework fine for all the options except ALL DC. I want to run some command which uses hostname and Ip.

Desired Output when ALL DC is input by the user is

This is my IP IP1 This is my hostname Host1 This is my IP IP2 This is my hostname Host2 This is my IP IP3 This is my hostname Host3 This is my IP IP4 This is my hostname Host4 This is my IP IP5 This is my hostname Host5

Answer 1

If I understand what you are trying to do correctly, I would probably not use separate arrays for this, but one single array containing objects in order to keep the units, ip's and hostnames together.

Then you could do:

$units = [PsCustomObject]@{unit = 'zone1'  ; ip = 'IP1'; hostname = 'Host1'},
         [PsCustomObject]@{unit = 'site2'  ; ip = 'IP2'; hostname = 'Host2'},
         [PsCustomObject]@{unit = 'unit5'  ; ip = 'IP3'; hostname = 'Host3'},
         [PsCustomObject]@{unit = 'region3'; ip = 'IP4'; hostname = 'Host4'},
         [PsCustomObject]@{unit = 'zone5'  ; ip = 'IP5'; hostname = 'Host5'}

$data = Read-Host -Prompt 'Please enter the unit'

$choice = if (![string]::IsNullOrWhiteSpace($data)) { $units | Where-Object { $_.unit -match $data }}
if ($choice) {
    Write-Host "You have chosen:" -ForegroundColor Green
    $choice | Format-Table -AutoSize
}
else {
    Write-Host "You have given invalid input.." -ForegroundColor Red
    Write-Host "These are all DC's:"
    $units | Format-Table -AutoSize
}

Is that your intent? If not, please edit your question to make it more clear.

Answer 2

You can reduce the number of assignments required by using a switch instead of if/elseif/else, and then only picking the array indices (instead of the target items):

$indices = switch -regex ($data){
    'zone1' { 0 }
    'site2' { 1 } 
    'unit5' { 2 }
    'ALL DC' { 0..4 }
}

$Unity=$IP[$indices]
$show=$hostname[$indices]

Now you just need to replace the foreach loop with a for loop:

for($i = 0; $i -lt $Indices.Length; $i++){
  $u = $Unity[$i]
  $h = $show[$i]

  echo "This is my IP" $u
  echo "This is my hostname" $h
}

---

Alternatively, construct objects based on the original arrays before letting the user choose:

$IP=@("IP1","IP2","IP3", "IP4" , "IP5")
$Hostname=@("Host1","Host2","Host3","HOST4", "HOST5")

# construct a new array of objects with corresponding IP-Host details
$HostIPDetails = for($i = 0; $i -lt $IP.Length; $i++){
  [pscustomobject]@{ IP = $IP[$i]; HostName = $Hostname[$i] }
}

$data = Read-Host 'Input the data... '

$indices = switch -regex ($data){
    'zone1' { 0 }
    'site2' { 1 } 
    'unit5' { 2 }
    'ALL DC' { 0..4 }
}

foreach($machine in $HostIPDetails[$indices]){
  echo "This is my IP" $machine.IP
  echo "This is my hostname" $machine.HostName 
}