Thank you Devin and all who responded – this makes sense and I will be using
this to declare new arrays (albeit difficult to remember).
The last formatting part is not working because there’s nothing to be piped
apparently
PS C:\WINDOWS\system32> foreach ($comp in $array){Test-Connection $comp -Count
1} | select Destination, IPv4Address
At line:1 char:59
+ foreach ($comp in $array){Test-Connection $comp -Count 1} | select De ...
+ ~
An empty pipe element is not allowed.
+ CategoryInfo : ParserError: (:) [],
ParentContainsErrorRecordException
+ FullyQualifiedErrorId : EmptyPipeElement
PS C:\WINDOWS\system32> foreach ($comp in $array){Test-Connection $comp -Count
1} | gm
At line:1 char:59
+ foreach ($comp in $array){Test-Connection $comp -Count 1} | gm
+ ~
An empty pipe element is not allowed.
+ CategoryInfo : ParserError: (:) [],
ParentContainsErrorRecordException
+ FullyQualifiedErrorId : EmptyPipeElement
PS C:\WINDOWS\system32> foreach ($comp in $array){Test-Connection $comp -Count
1 | select Destination,IPv4Address}
Destination IPV4Address
----------- -----------
172.29.133.130
172.29.118.101
172.29.171.28
172.29.118.164
Thank you,
Ray
From: [email protected] [mailto:[email protected]] On
Behalf Of Devin Rich
Sent: Thursday, October 19, 2017 10:58 AM
To: [email protected]
Subject: Re: [powershell] Powershell array question and formatting question
Hi Ray,
Welcome to the world of guessing! Where the powershell developers had to guess
which type of arrays to give you by default. In Powershell, there are arrays
that are static (fixed length), and real arrays like you know from C#, etc. In
powershell, $a = 1,2,3 will give you one of those static arrays. if you then do
$a += 4, it will create a new array of length $a.Count + 1 and copy all
contents of $a into the new array before populating the final item with the 4.
This is why doing looping with += will in cases with lots of loops or larger
datasets waste a TON of CPU creating and deleting useless arrays. In order to
get the arraylist that you are thinking of using (that can .add() and
.remove()), you need to use ArrayList from Syste,Collections. Also, -= is not a
thing for powershell. Consider this example:
[Inline image 1]
And I could just as easily do:
PS C:\downloads> [System.Collections.ArrayList]$a = 1,2,3
PS C:\downloads> $a.Remove(2)
PS C:\downloads> $a
1
3
PS C:\downloads> $a.Remove(3)
PS C:\downloads> $a
1
Lastly, select should work fine:
foreach ($comp in $array){Test-Connection $comp -Count 1} | Select Destination,
IPv4Address
foreach ($comp in $array){Test-Connection $comp -Count 1 | Select Destination,
IPv4Address }
These are functionally the same, but in case 1, it will gather all results from
the foreach before piping to a single select. Case 2 will pipe each result to
select before going onto the next iteration. Just a style choice there for you.
Thanks,
Devin Rich
Systems Administrator
On Thu, Oct 19, 2017 at 11:33 AM, Raymond Peng
<[email protected]<mailto:[email protected]>> wrote:
Hi All,
Still picking up powershell so please let me know if you see any obvious
blunders: I see it say the collection is of a fixed size but how do I remove?
I have declared an array with $array=”name1”,”name2”, etc…
I can access each element with $array[0]…
I can use $array += “name5,”name6” but I can not figure out how to remove an
element
I have tried the Remove method without any luck as well as -=
PS C:\WINDOWS\system32> $array.Remove("cxsupportsystems")
Exception calling "Remove" with "1" argument(s): "Collection was of a fixed
size."
At line:1 char:1
+ $array.Remove("cxsupportsystems")
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : NotSupportedException
PS C:\WINDOWS\system32> $array
kcfileserver
wnweb01
pvfile01
corpcxtsgp01
cxsupportsystems
Lastly – formatting question:
Is there any way to just crop out the rest and keep the destination /
IPv4Address info? I tried format-table / select-object but it does not do what
I want. I’ve tried piping after the test-connection in the scriptblock but
output is not what I want
PS C:\WINDOWS\system32> foreach ($comp in $array){Test-Connection $comp -Count
1}
Source Destination IPV4Address IPV6Address
Bytes Time(ms)
------ ----------- ----------- -----------
----- --------
L-SM-RPENG1 kcfileserver 172.29.133.130
32 62
L-SM-RPENG1 wnweb01 172.29.118.101
32 66
L-SM-RPENG1 pvfile01 172.29.171.28
32 72
L-SM-RPENG1 corpcxtsgp01 172.29.118.164
32 70
L-SM-RPENG1 cxsupportsys... 10.2.1.238
32 55
Thank you,
Ray
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