foreach-object question

why does this not work:
foreach-object {
begin { foo }
process { foo }
end { foo }
}

I get this error:
ForEach-Object : The script block cannot be invoked because it contains more
than one clause. The Invoke() method can only be used on script blocks
containing
a single clause.
At line:1 char:49
+ $users | select-object -first 5 | foreach-object <<<< {

Any guidance is most appreciated. Thanks in advance.
--
v(^_^)v

get-help about_foreach

Never Mind.

foreach-object has it's script blocks assigned via parameters and creates
it's own complete scriptblock, so you need to do this:

foreach-object -begin { "foo" } -process { "foo" } -end { "foo" }

internally, foreach creates a complete script block out of the pieces



--
--
James Truher [MSFT]
Windows PowerShell Development
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.

"~Clint" <Clint@discussions.microsoft.com> wrote in message
news:C11382C1-07AD-4AC8-9513-8CF2828879F3@microsoft.com...
> why does this not work:
> foreach-object {
> begin { foo }
> process { foo }
> end { foo }
> }
>
> I get this error:
> ForEach-Object : The script block cannot be invoked because it contains
> more
> than one clause. The Invoke() method can only be used on script blocks
> containing
> a single clause.
> At line:1 char:49
> + $users | select-object -first 5 | foreach-object <<<< {
>
> Any guidance is most appreciated. Thanks in advance.
> --
> v(^_^)v

"James Truher" <jimtru@news.microsoft.com> wrote in message
news:%234gx5u2AHHA.3316@TK2MSFTNGP02.phx.gbl...
> foreach-object has it's script blocks assigned via parameters and creates
> it's own complete scriptblock, so you need to do this:
>
> foreach-object -begin { "foo" } -process { "foo" } -end { "foo" }

Alternatively you can do this:

1..5 | & {begin{"foo"}process{"foo"}end{"foo"}}

or

1..5 | & {process{"p"}}

Sometimes I prefer this to foreach-object because it maps better to my
mental model of using an anonymous PoSH function/scriptblock in the pipeline
versus "iteration" that is implied by the name "foreach". I always have a
hard time explaining foreach-each since I have usually just explained that
objects are passed down the pipeline one at a time to the next stage by the
object flow engine. So the question that usually comes up is "then why do I
need to iterate over individual pipeline objects?". If you have a better
way to explain this I would appreciate hearing it. One benefit of the
cmdlet foreach-object is that you get the functionality given by the
ubiqitous parameters (-ErrorAction, etc).

--
Keith