Use Variable for Select-Object or Format-Table

Question

I have a a similar question like this: Question 44460843

I want to use variables for the fields.

This example works well:

$x = ("Id,ProcessName,CPU").split(",")
Get-Process | ft -a $x

But how do i get it, if i want custom fields like this?

Get-Process | ft -a Id,ProcessName,@{Name = 'CPUx' ; Expression = {$_.CPU}}

I tried this, but it don't works:

$x = ("Id,ProcessName,@{Name = 'CPUx' ; Expression = {$_.CPU}}").split(",")
Get-Process | ft -a $x

Does anybody know how to do this? I am a lazy guy and want to avoid this copy/paste orgies with long text.

that looks like the `splatting` idea. take a look at `Get-Help about_Splatting` for how that works. [*grin*] — Lee_Dailey, Mar 30 '22 at 12:51
`$x = 'Id','ProcessName',@{Name = 'CPUx' ; Expression = {$_.CPU}}; Get-Process | ft -a $x` — Theo, Mar 30 '22 at 13:08

mklement0 · Accepted Answer · 2022-03-30T22:55:48.987

Note:

The answer applies analogously to the Select-Object cmdlet, which is what should be used to extract properties for later programmatic processing.
Format-* cmdlets, such as Format-Table in this case (whose built-in alias is ft), are only intended to produce for-display formatting; see this answer for more information.

Theo has provided the solution in a comment:

$x = 'Id', 'ProcessName', @{ Name = 'CPUx' ; Expression = { $_.CPU } }
Get-Process | Format-Table -AutoSize $x  # same as: ft -a $x

That is, the answer to the linked question applies in your case as well, even though it happens to use only literal strings as property names:

Directly construct an array of property names and calculated properties, using ,, the array constructor operator, which allows you to use any mix of literals and variables; e.g.:

$pName = 'processName'                               # property name
$pCpu = @{ Name = 'CPUx' ; Expression = { $_.CPU } } # calculated property

$x = 'Id', $pName, $pCpu

Do not start with a single string that you split into an array of tokens with .Split(), because it will limit you to property names, given that the tokens are invariably strings.

As an aside:

The array binds positionally to Format-Table's (ft's) -Property parameter, and you can easily discover that as well as the fact that an array of property names / calculated properties is discovered as follows:

PS> Format-Table -?
...

SYNTAX
    Format-Table [[-Property] <System.Object[]>] ...

DESCRIPTION
...

The outer [...] tells you that the parameter is optional as a whole.
The [...] around -Property tells you that specifying the parameter name explicitly is optional, i.e. that positional binding is supported.
<System.Object[]> tells you that an array ([]) of System.Object instances is expected as the type of the argument(s).

To get more information about what objects, specifically, may be passed, inspect the parameter individually:

PS> Get-Help Format-Table -Parameter Property

-Property <System.Object[]>
    Specifies the object properties that appear in the display and the order 
    in which they appear. Type one or more property names, separated 
    by commas, or use a hash table to display a calculated property. 
    Wildcards are permitted.
...

Use Variable for Select-Object or Format-Table

1 Answers1