从基于文本的表输出中提取列

Question

qfarm /load 命令显示来自我的服务器的负载。 输出：

PS> qfarm /load

Server Name           Server Load  Load Throttling Load  Logon Mode
--------------------  -----------  --------------------  ------------------
SERVER-01             400          0                     AllowLogons
SERVER-02             1364         OFF                   AllowLogons
SERVER-03             1364         OFF                   AllowLogons
SERVER-04             1000         0                     AllowLogons
SERVER-05             700          0                     AllowLogons
SERVER-06             1200         0                     AllowLogons

我只需要显示第一列（服务器名称）和第二列（服务器负载）并循环遍历它们，以便稍后制作一些逻辑，但似乎 powershell 没有将其视为具有属性的对象：

PS> qfarm /load | Select -ExpandProperty "Server Name"
Select-Object : Property "Server Name" cannot be found.

还有其他可能吗，比如桌子什么的？

Answer 1

一种方法是从命令的输出中构建对象。测试了以下内容：

#requires -version 3

# sample data output from command
$sampleData = @"
Server Name           Server Load  Load Throttling Load  Logon Mode
--------------------  -----------  --------------------  ------------------
SERVER-01             400          0                     AllowLogons
SERVER-02             1364         OFF                   AllowLogons
SERVER-03             1364         OFF                   AllowLogons
SERVER-04             1000         0                     AllowLogons
SERVER-05             700          0                     AllowLogons
SERVER-06             1200         0                     AllowLogons
"@ -split "`n"

$sampleData | Select-Object -Skip 2 | ForEach-Object {
  $len = $_.Length
  [PSCustomObject] @{
    "ServerName"         = $_.Substring(0,  22).Trim()
    "ServerLoad"         = $_.Substring(22, 13).Trim() -as [Int]
    "LoadThrottlingLoad" = $_.Substring(35, 22).Trim()
    "LogonMode"          = $_.Substring(57, $len - 57).Trim()
  }
}

在您的情况下，您应该能够用您的 qfarm load 命令替换 $sampleData；例如：

qfarm /load | Select-Object -Skip 2 | ForEach-Object {
...

当然，这是假设输出中没有空行，并且我的每个项目开头的列位置是正确的。

PowerShell 版本 2 等效项：

#requires -version 2

function Out-Object {
  param(
    [Collections.Hashtable[]] $hashData
  )
  $order = @()
  $result = @{}
  $hashData | ForEach-Object {
    $order += ($_.Keys -as [Array])[0]
    $result += $_
  }
  New-Object PSObject -Property $result | Select-Object $order
}

# sample data output from command
$sampleData = @"
Server Name           Server Load  Load Throttling Load  Logon Mode
--------------------  -----------  --------------------  ------------------
SERVER-01             400          0                     AllowLogons
SERVER-02             1364         OFF                   AllowLogons
SERVER-03             1364         OFF                   AllowLogons
SERVER-04             1000         0                     AllowLogons
SERVER-05             700          0                     AllowLogons
SERVER-06             1200         0                     AllowLogons
"@ -split "`n"

$sampleData | Select-Object -Skip 2 | ForEach-Object {
  $len = $_.Length
  Out-Object `
    @{"ServerName"         = $_.Substring(0,  22).Trim()},
    @{"ServerLoad"         = $_.Substring(22, 13).Trim() -as [Int]},
    @{"LoadThrottlingLoad" = $_.Substring(35, 22).Trim()},
    @{"LogonMode"          = $_.Substring(57, $len - 57).Trim()}
}

Answer 2

您可以使用PowerShell Gallery 中的ConvertFrom-SourceTable cmdlet 轻松地将表转换为 PowerShell 对象：

$sampleData = ConvertFrom-SourceTable @"
Server Name           Server Load  Load Throttling Load  Logon Mode
--------------------  -----------  --------------------  ------------------
SERVER-01             400          0                     AllowLogons
SERVER-02             1364         OFF                   AllowLogons
SERVER-03             1364         OFF                   AllowLogons
SERVER-04             1000         0                     AllowLogons
SERVER-05             700          0                     AllowLogons
SERVER-06             1200         0                     AllowLogons
"@

然后选择您的列，例如：

PS C:\> $SampleData | Select-Object "Server Name", "Server Load"

Server Name Server Load
----------- -----------
SERVER-01   400
SERVER-02   1364
SERVER-03   1364
SERVER-04   1000
SERVER-05   700
SERVER-06   1200

详情见：ConvertFrom-SourceTable -?

_{ConvertFrom-SourceTable cmdlet 可从 PowerShell 库下载，源代码可从 GitHub iRon7/ConvertFrom-SourceTable 存储库下载。}

Answer 3

命令行实用程序将其输出作为字符串数组返回。这应该有效：

qfarm /load | ForEach-Object { $_.Substring(0,33) }

Answer 4

I have answered something very similar to this in the past。我对此有一个更大的功能，但正如您在示例中所展示的那样，简化了左对齐字符串表的工作。有关详细说明，请参阅链接的答案。

function ConvertFrom-LeftAlignedStringData{
    param (
        [string[]]$data
    )

    $headerString = $data[0]
    $headerElements = $headerString -split "\s{2,}" | Where-Object{$_}
    $headerIndexes = $headerElements | ForEach-Object{$headerString.IndexOf($_)}

    $results = $data | Select-Object -Skip 2  | ForEach-Object{
        $props = @{}
        $line = $_
        For($indexStep = 0; $indexStep -le $headerIndexes.Count - 1; $indexStep++){
            $value = $null            # Assume a null value 
            $valueLength = $headerIndexes[$indexStep + 1] - $headerIndexes[$indexStep]
            $valueStart = $headerIndexes[$indexStep]
            If(($valueLength -gt 0) -and (($valueStart + $valueLength) -lt $line.Length)){
                $value = ($line.Substring($valueStart,$valueLength)).Trim()
            } ElseIf ($valueStart -lt $line.Length){
                $value = ($line.Substring($valueStart)).Trim()
            }
            $props.($headerElements[$indexStep]) = $value    
        }
        New-Object -TypeName PsCustomObject -Property $props
    } 

    return $results
}


$qfarmOutput = qfarm /load
ConvertFrom-LeftAlignedStringData $qfarmOutput | select "Server Name","Server Load"

此方法基于标头字段的位置。没有什么是硬编码的，它都是基于这些索引和字段名称自定义构建的。使用这些$headerIndexes，我们分割每一行并将结果（如果存在）放入其各自的列中。有逻辑可以确保我们不会尝试抓取可能不存在的字符串的任何部分并将最后一个字段视为特殊字段。

结果

Server Name Server Load
----------- -----------
SERVER-01   400        
SERVER-02   1364       
SERVER-03   1364       
SERVER-04   1000       
SERVER-05   700        
SERVER-06   1200