[PowerShell] [astuce] 'Where' à la 'LINQ' avec PowerShell 2.0

'Where' à la 'LINQ' avec PowerShell 2.0

Salut,

cette petite astuce est une amélioration de la nouvelle syntaxe declarative 'Where' en PS 4.0

Code:

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<?xml version="1.0" encoding="utf-8" ?>
<Types>
    <Type>
        <Name>System.Array</Name>
        <Members>
             <ScriptMethod>
                <Name>Where</Name>
                <Script>
    $arg = $args[0] -as [String]
    $members = ($this |gm -Type *property |select -Unique -Expand name) +'PSItem'
    $members | foreach {
                 if($arg -match $_) {
                    if($Matches[0] -eq 'PSItem')
                    { $arg=$arg.replace($($Matches[0]),'$_')
                    }
                    else 
                    { $arg=$arg.replace($($Matches[0]),$('$_.' + $Matches[0]))
                    } 
                 }
               }
     $sb=$ExecutionContext.InvokeCommand.NewScriptBlock($arg)
     $this | Where-Object -Filter $sb
                </Script>
            </ScriptMethod>
        </Members>
    </Type>
</Types>

après avoir updater votre fichier de configuration vous pouvez l'utiliser ainsi:

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PS II> (1..10).Where('PSitem -gt 5 -and (PSitem -band 1)')
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9

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PS II> $dir = Get-ChildItem c:\Temp
PS II> $dir.Where('!psiscontainer -and length -gt 10mb')


    Répertoire*: c:\Temp


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---        10/02/2012     13:30       12mb f35.exe

Code:

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PS > $dir.Where('$true')


    Répertoire*: c:\Temp


Mode                LastWriteTime     Length Name
----                -------------     ------ ----
d----        01/05/2012     18:22            Scripts
-a---        10/02/2012     13:30       12mb f35.exe

Code:

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PS II> (get-process).Where('path -like "*Scripts*"').Where('StartTime')
PS II> # ou bien:
PS II> (get-process).Where('path -like "*Scripts*" -and StartTime')

<?xml version="1.0" encoding="utf-8" ?> <Types> <Type> <Name>System.Array</Name> <Members> <ScriptMethod> <Name>Where</Name> <Script> $arg = $args[0] -as [String] $members = ($this |gm -Type *property |select -Unique -Expand name) +'PSItem' $members | foreach { if($arg -match "\b$_\b") { if($Matches[0] -eq 'PSItem') { $arg=$arg -replace "(?<=\W|^)$_\b",'$$_' } else { $arg=$arg -replace "(?<=\W|^)$_\b",'$$_.$0' } } } $sb=$ExecutionContext.InvokeCommand.NewScriptBlock($arg) $this | Where-Object -Filter $sb </Script> </ScriptMethod> </Members> </Type> </Types>

PS II> (0:0:0 421,00) PS > $items.Where("!PSISContainer -and (Length -gt 2mb -or basename -like '*e')") Répertoire*: D:\WINDOWS Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 30/04/2011 16:55 0 Trace.log -a--- 05/08/2013 06:54 5.6mb Win3.log

PS II> (get-process).where("StartTime -and Path -and name.length -lt 4") Handles NPM(K) PM(K) WS(K) VM(M) CPU(s) Id ProcessName ------- ------ ----- ----- ----- ------ -- ----------- 40 3 1028 3456 31 0,28 1496 osk