PowerShell: Append to an array from a file

Posted on 2010-09-07
Last Modified: 2012-05-10
I have the following code that is used to populated a $ServerList (starting a $ServerList[1]), but I'd also like to be able to read a file of servernames... and append those names to the end of the ServerList string type.

The issue is, that $ServerList is a pre-dementioned array.  That reason for this is because I get the error:

"Cannot index into a null array."

If attempt to run the code below:

# Grab list of servers use QAD then select the name object, and then short the results by the name

$a = (Get-QADComputer -OSName 'Windows*Server*' | Select-Object name | Sort-Object name )
$b = ($a | ForEach-Object {$})

# Create the list of servers array, but start the elements from 1, not zero.

$ServerList = New-Object string[] ($b.Count+2)

for ($j=0; $j -le $b.count; $j++) { $ServerList[$j+1]=$b[$j]}

As yiu can see, there is a whole lot of swapping going on here... primarily because the output of $a gives me headers, and the populating of $b starts at zero (e.g. $b[0]).  Which causes issues with friggen Excel, so we then dump the contents of $b into $ServerList.

So then I take a CSV file, and I want to add it to the $ServerList array, but I get an ERROR... because the array is not dimmensioned to fit to additional strings:

# Load CSV list of additional servers NOT on the Domain and add them to the list of servers

$a = Import-Csv y:\AddititionalServerList.csv
$b = ($a | ForEach-Object {$})

What I'd like to do, is simply append these to the end of the $ServerList array:

$ServerList = $ServerList+$b

But that doesn't work...

Can anyone work this out for me?

Question by:gerhardub
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 13

Accepted Solution

soostibi earned 500 total points
ID: 33625674
I do not exactly know, why it does not work for you, as it workes for me.
But anyway, the code is not very nice and efficient.
My suggestion is this (you can change the text "insertion" in the last line to anything):
$serverlist = [collections.arraylist] (@(Get-QADComputer -OSName 'Windows*Server*' | Select-Object -ExpandProperty name), 
    @(import-csv y:\AddititionalServerList.csv | Select-Object -ExpandProperty name) | %{$_} | Sort-Object)

Open in new window


Author Closing Comment

ID: 33627556

I figure a few hundred more learning experiences like this and I'll actually know what I'm doing.

That's exactly the information I needed to fix this.

Thank YOU!

Featured Post

Why You Need a DevOps Toolchain

IT needs to deliver services with more agility and velocity. IT must roll out application features and innovations faster to keep up with customer demands, which is where a DevOps toolchain steps in. View the infographic to see why you need a DevOps toolchain.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Auditing domain password hashes is a commonly overlooked but critical requirement to ensuring secure passwords practices are followed. Methods exist to extract hashes directly for a live domain however this article describes a process to extract u…
Recently we ran in to an issue while running some SQL jobs where we were trying to process the cubes.  We got an error saying failure stating 'NT SERVICE\SQLSERVERAGENT does not have access to Analysis Services. So this is a way to automate that wit…
This video Micro Tutorial explains how to clone a hard drive using a commercial software product for Windows systems called Casper from Future Systems Solutions (FSS). Cloning makes an exact, complete copy of one hard disk drive (HDD) onto another d…
In this video, we discuss why the need for additional vertical screen space has become more important in recent years, namely, due to the transition in the marketplace of 4x3 computer screens to 16x9 and 16x10 screens (so-called widescreen format). …

710 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question