Review help-topic example code for best practices, such as avoiding unnecessary $(...)

[mklement0]

The practices shown in example code are important, because inexperienced users will naturally assume that such code reflects best practices.

This is currently not always the case, as the following example demonstrates; in addition to this specific case, I think a systematic review of example code is worth doing.

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The Compare-Object topic currently contains this hashtable definition:

$objects = @{
 ReferenceObject = $(Get-Content -Path C:\Test\Testfile1.txt)
 DifferenceObject = $(Get-Content -Path C:\Test\Testfile2.txt)
}

Not only is the $(...) around the Get-Content commands unnecessary, using $(...) has the potential to modify the command's output.

^{Note: There is very specific Windows PowerShell bug where an if statement without an else block in a hashtable literal fails without $(...), but only if the if statement isn't the last entry.}

To use a contrived example:

PS> @{ foo = $(, 1) }.foo.GetType().Name
Int32  # Single-element array was unwrapped by $()

Similarly, (...), not $(...), should be used when output from a single command or expression is passed as a command argument (e.g., Write-Output (Get-Date), not Write-Output $(Get-Date).

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Document Details

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• ID: a7615306-98e3-0b79-ac87-58bb191b4349
• Version Independent ID: 85f1e969-8216-bed4-2204-409cbd9befd4
• Content: Compare-Object (Microsoft.PowerShell.Utility)
• Content Source: reference/6/Microsoft.PowerShell.Utility/Compare-Object.md
• Product: powershell
• Technology: powershell-cmdlets
• GitHub Login: @JamesWTruher
• Microsoft Alias: jimtru