Question

为什么我的循环只发生一次？我想输入5个用户并将其添加到哈希表中，但代码运行一次然后停止。我该如何解决？

$userID=""
$firstname=""  
$lastname="
$personCount = 1
$personHash = @{}

while ($personCount -le 5){
    $personCount++
    While([string]::IsNullOrWhiteSpace($userID)){
        $userID = Read-Host "Enter ID"
    }
    While([string]::IsNullOrWhiteSpace($firstname)){
        $firstname = Read-Host "Enter First Name"
    }
    While([string]::IsNullOrWhiteSpace($lastname)){
        $lastname = Read-Host "Enter Last Name"
    }

    $user = New-Object PSCustomObject -Property @{
        ID = $userID
        FirstName = $firstname
        LastName = $lastname
    }
    $personHash.Add($user.ID,$user)
}
}

输出：

Enter ID: 1001
Enter First Name: Charles
Enter Last Name: Whitfield

Name       Value
----       -----
1001       @{ID=1001; FirstName=Charles; LastName=Whitfield}
1001       @{ID=1001; FirstName=Charles; LastName=Whitfield}
1001       @{ID=1001; FirstName=Charles; LastName=Whitfield}
1001       @{ID=1001; FirstName=Charles; LastName=Whitfield}

Answer 1

你的循环运行5次。

问题是，一旦变量在第一个循环中填充，它们就会在所有后续循环中失败。它运行一次，执行读取主机并设置变量。然后再运行4次，但找不到任何事情。

您的更新代码更近了。您保存数据，但没有清除下一个循环的变量。

$userID=""
    $firstname=""  
    $lastname=""
    $personCount = 1
    $personHash = @{}

        while ($personCount -le 5){
            $personCount++
            While([string]::IsNullOrWhiteSpace($userID)){
                $userID = Read-Host "Enter ID"
            }
            While([string]::IsNullOrWhiteSpace($firstname)){
                $firstname = Read-Host "Enter First Name"
            }
            While([string]::IsNullOrWhiteSpace($lastname)){
                $lastname = Read-Host "Enter Last Name"
            }

         $user = New-Object PSCustomObject -Property @{
         ID = $userID
         FirstName = $firstname
         LastName = $lastname}

         $personHash.Add($user.ID,$user)

         $UserID,$firstname,$lastname = ""
    }

Answer 2

这里有几个问题，while循环需要明确的变量，如mjolinor所说。完成后，我建议将数据保存在一个数组中，这样每个用户的数据都不会在下一次迭代中丢失：

$users = @()
$personCount = 1

while ($personCount -le 5){
    $userID=""
    $firstname=""  
    $lastname=""
    $personCount++

    While([string]::IsNullOrWhiteSpace($userID)){
        $userID = Read-Host "Enter ID"
    }
    While([string]::IsNullOrWhiteSpace($firstname)){
        $firstname = Read-Host "Enter First Name"
    }
    While([string]::IsNullOrWhiteSpace($lastname)){
        $lastname = Read-Host "Enter Last Name"
    }
    $users += New-Object -TypeName PSCustomObject -Property @{
        userID    = $userID;
        firstName = $firstname;
        lastName  = $lastname
    }
}

数组$ users包含所有数据后，您可以使用$users或具有$users[0]，$users[1]等的特定用户一次性输出所有值。

Answer 3

您发布的代码显然不可能创建您发布的输出。即使我对这两个语法错误进行了折扣，您仍然会获得4个关键冲突异常，因为您尝试将相同的密钥添加到同一个哈希表中5次（哈希表中的密钥必须是唯一的）。

如果要在哈希表中创建5个用户对象，并确保用户为所有3个属性输入值，如果您希望重复ID引发错误，则可以执行类似这样的操作：

$personHash = @{}

1..5 | % {
  do {
    $userID    = Read-Host "Enter ID"
    $firstname = Read-Host "Enter First Name"
    $lastname  = Read-Host "Enter Last Name"
  } until ( $userID -and $firstname -and $lastname )

  $user = New-Object -Type PSCustomObject -Property @{
            'ID'        = $userID
            'FirstName' = $firstname
            'LastName'  = $lastname
          }

  $personHash.Add($userID, $user)
}

或者像这样，如果你想要一个重复的ID来更新当前值：

$personHash = @{}

1..5 | % {
  do {
    $userID    = Read-Host "Enter ID"
    $firstname = Read-Host "Enter First Name"
    $lastname  = Read-Host "Enter Last Name"
  } until ( $userID -and $firstname -and $lastname )

  $user = New-Object -Type PSCustomObject -Property @{
            'ID'        = $userID
            'FirstName' = $firstname
            'LastName'  = $lastname
          }

  $personHash[$userID] = $user
}

Powershell While循环问题

3 个答案: