如何自动创建和使用变量名？

Question

我有 10 个变量，称为 rows($row1, $row2, $row3...)，我需要用户从其中一个变量中进行选择，只知道正确的行，我很难理解如何连接文本到一个变量，对应另一个变量并获取值，而不是写成文本

$ChoosenRow = Read-Host
$rownumber = $("row" + $ChoosenRow)
$IP = Write-Output $rownumber 

如果我输入 10，我会得到 $IP = row10 我试图让 $IP 成为 $row10 的值，而不是字符串。

对不起，我的英语不好和我的愚蠢问题，我试图搜索类似的问题，但没有找到任何

编辑：iRon 让我添加更多脚本：

# Carica il file e crea le variabili per il file
$FilePath = '\\ntced\CED\AssistenzaPC\IP IN GESTIONE\2021-08-16 TabellaIP.xls'
$xl = New-Object -ComObject Excel.Application
$xl.Visible = $true
$wb = $xl.Workbooks.Open($filepath)

# Prendi la prima colonna
$data = $wb.Worksheets['Foglio1'].UsedRange.Rows.Columns[1].Value2
$data2 = $wb.Worksheets['Foglio1'].UsedRange.Rows.Columns[2].Value2

# Chiudi excel aperto per prendere i dati
$wb.close()
$xl.Quit()
While([System.Runtime.Interopservices.Marshal]::ReleaseComObject($wb) -ge 0){}
while([System.Runtime.Interopservices.Marshal]::ReleaseComObject($xl) -ge 0){} 
Remove-Variable xl,wb # Rimuovi le due variabili create

# display results
$data | select -skip 1 # Rimuove il titolo sopra

# Variabili degli IP

$variables = @()
$i = 0
foreach ($row in ($data -split [Environment]::NewLine)) {
  # Crea una variabile per ogni riga
  New-Variable -Name "row$i" -Value $row
  # e un membro dell'array
  $variables += [pscustomobject]@{Name = "row$i"; Value = $row} # Copiato male, era troppo complicato arrivarci
  $i++
}

$variables2 = @()
$ii = 0
foreach ($linea in ($data2 -split [Environment]::NewLine)) {
  # Crea una variabile per ogni riga
  New-Variable -Name "linea$ii" -Value $linea
  # e un membro dell'array
  $variables2 += [pscustomobject]@{Name = "linea$ii"; Value = $linea} 
  $ii++
}

function Show-Menu
{
 param (
 [string]$Title = 'Scegli IP'
 )
 Clear-Host
 Write-Host "================ $Title ================"
 Write-Host "1: Cambia IP da tabella IP nuovi"
 Write-Host "Q: premi 'Q' per uscire."
}

Show-Menu –Title 'Scegli IP'
$selection = Read-Host 'Scegli la'

switch ($selection)
 {
     '1' {
         ' Scrivi la linea che contiene IP libero'

         $LineaScelta = Read-Host
         $rownumber = $("row" + $LineaScelta)

          $IP = Write-Output $rownumber
          $MaskBits = 20 # subnet mask in bits = 255.255.240.0
          $Gateway = "172.16.111.254"
          $Dns = "172.16.16.1"
          $IPType = "IPv4"
     } 

     'q' { 
           return
         }
 }

  # Imposta su tutte le schede di rete attive, quindi tenere acceso solo quella necessaria!
$adapter = Get-NetAdapter | ? {$_.Status -eq "up"}

# Rimuove gli IP prima di metterli 
If (($adapter | Get-NetIPConfiguration).IPv4Address.IPAddress) {
 $adapter | Remove-NetIPAddress -AddressFamily $IPType -Confirm:$false
}

If (($adapter | Get-NetIPConfiguration).Ipv4DefaultGateway) {
 $adapter | Remove-NetRoute -AddressFamily $IPType -Confirm:$false
}

 # Configura gli IP, CHE BESTEMMIE PER CAPIRE COME USARE

$adapter | New-NetIPAddress `
 -AddressFamily $IPType `
 -IPAddress $IP `
 -PrefixLength $MaskBits `
 -DefaultGateway $Gateway

# Configura il primo server DNS, non so come configurare il secondo ancora.
$adapter | Set-DnsClientServerAddress -ServerAddresses $DNS

Answer 1

一般（最佳实践）建议：

不要将<verb>-Variable cmdlets 用于动态变量名！

_{(Rule request: #1706 Warning if Set/Get-Variable is invoked with only the basic -Name/-Value parameters.)}

背景

PowerShell（与几乎所有其他编程语言一样）有一个内部字典，它保留所有变量名称和对其包含值的（直接或间接）引用。字典基于binary search algorithm，以便能够快速找到与具体变量名相关的值。

为什么不呢？

为特定值创建任何（唯一）变量名称是一种通用用法，但此时您发现您的程序不再是 DRY 并开始使用使用 @ 的语句自动执行变量名称本身987654333@，如：New-Variable -Name "row$i" -Value $row，您可能会失去疏忽甚至与其他变量名发生冲突。相反，您最好使用hashtable（也基于二进制搜索）创建自己的自定义字典。

怎么做？

而不是这个：

$variables = @()
$i = 0
foreach ($row in ($data -split [Environment]::NewLine)) {
  # Crea una variabile per ogni riga
  New-Variable -Name "row$i" -Value $row
  # e un membro dell'array
  $variables += [pscustomobject]@{Name = "row$i"; Value = $row} # Copiato male, era troppo complicato arrivarci
  $i++
}

你可以这样做：

$Rows = @{}
$i = 0
foreach ($row in ($data -split [Environment]::NewLine)) { $Rows[$i++] = $Row }

并获取具体值：

$LineaScelta = Read-Host
$IP = $Rows[[Int]$LineaScelta]

由于字典的键似乎是一个连续的从零开始的数字系列，您甚至可以使用数组进一步简化它：

$Rows = $data -split [Environment]::NewLine

$LineaScelta = Read-Host
$IP = $Rows[$LineaScelta]

_{作为侧节点：也是try I avoid using the increase assignment operator (+=) to create a collection}