Vista - commas in PowerShell

This works
get-help about* | Format-Table -Property Name, Synopsis

This does not work
get-help about* | Format-Table -Property Name Synopsis

What is the significance of that comma that makes the first version meaningful?

- Larry

get-help about* | Format-Table -Property Name, Synopsis
this works because Name and Synopsis are passed as array to -Property
parameter.

get-help about* | Format-Table -Property Name Synopsis
this doesn't work, because space is delimiter between parameters. Therefore
PowerShell tries to bind "Synopsis" to the next positional paramter and
uneble to find. The same behaviour is with passing arguments to functions.
If you pass arguments separating them with coma - they will passed as array
and single argument. If you separate arguments with spaces - each parameter
will be passed as different argument.
--
WBR, Vadims Podans
MVP: PowerShell
PowerShell blog - www.sysadmins.lv

"Larry__Weiss" <lfw@xxxxxx> rakstija zinojuma
"news:ukPAzvlAKHA.1380@xxxxxx"...

Yeah, in short: commas make arrays, just like @() does. It works on
parameters which take arrays, or on assignments:

$foo = 1,2,3 # foo is an array of objects containing three numbers
$foo = @(1,2,3) # foo is an array of objects containing three numbers
$foo = ,1 # foo is an array of objects containing a single number
$foo = @(1) # foo is an array of objects containing a single number

In each case $foo.GetType() will return Object[] (an array of Objects).
The only way to avoid getting an object array is to cast it specifically.



Vadims Podans [MVP] wrote:

Thanks!
I thought about it looking a lot like an array specification,
and tried different array syntax to try to confirm it.
For example,
get-help about* | Format-Table -Property @(Name, Synopsis)
but that would not work.

So with your confirmation that we are passing an array I now find that
get-help about* | Format-Table -Property @("Name", "Synopsis")
works fine (and takes any mystery out of it for me!)

As an aside,
I wonder if anyone has written a translator for the usual PowerShell
diagnostic verbiage? I don't know if I'll ever become fluent in that lingo.
I think that perhaps a more terse version would be less overwhelming.

For example for
get-help about* | Format-Table -Property @(Name, Synopsis)
I get

<#
The term 'Name' is not recognized as a cmdlet, function, operable program, or
script file. Verify t
he term and try again.
At line:1 char:48
+ get-help about* | Format-Table -Property @(Name <<<< , Synopsis)
+ CategoryInfo : ObjectNotFound: (Name:String) [],
CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
Format-Table : Object reference not set to an instance of an object.
At line:1 char:31
+ get-help about* | Format-Table <<<< -Property @(Name, Synopsis)
+ CategoryInfo : NotSpecified: ( [Format-Table],
NullReferenceException
+ FullyQualifiedErrorId :
System.NullReferenceException,Microsoft.PowerShell.Commands.FormatTa
bleCommand
#>

(At least it wraps words without "..." truncation.)

- Larry

Vadims Podans [MVP] wrote:

if you use @() notation then you must place inside parameters in quotes. In
first PS parser will try to convert to array object as in console and after
this object will be passed as arguments:

[↓] [vPodans] @("name", "synopsis")
name
synopsis
[↓] [vPodans] @(name, synopsis)
The term 'name' is not recognized as a cmdlet, function, operable program,
or script file. Verify the term and try agai
n.
At line:1 char:7
+ @(name <<<< , synopsis)
+ CategoryInfo : ObjectNotFound: (name:String) [],
CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

[↓] [vPodans]

first example is identical as Get-Help -property Name, Synopsis because it
already accept arrays (as mentioned Joel).
--
WBR, Vadims Podans
MVP: PowerShell
PowerShell blog - www.sysadmins.lv

"Larry__Weiss" <lfw@xxxxxx> rakstīja ziņojum�
"news:#nsAGemAKHA.2604@xxxxxx"...

Also: try to get used to the way the help info is formatted:

Format-Table [-DisplayError] [-ShowError] [-Force] [-InputObject
<psobject>] [
-Expand <string>] [-View <string>] [-HideTableHeaders] [-AutoSize]
[-Wrap] [-G
roupBy <Object>] [[-Property] <Object[]>] [<CommonParameters>]

Note that the -Property parameter expects an array of obects, indicated by
the [] characters, that means one or more values seperated by commas. The
View parameter e.g. accepts only one string, that is the name of a view.


"Vadims Podans [MVP]" <vpodans> wrote in message
news:uohaf3lAKHA.3696@xxxxxx