Powershell two dimensional array not working as expected

Question

At the moment I am loading in some data from an XML file to configure some parameters for my script to run, however the $keywords and $maxCounts are not getting the correct values when they are being sent to the CheckForKeywords function

function Main()
{

#### VARIABLES RELATING TO THE LOG FILE

#contains the log path and log file mask
$logPaths = @()
$logFileMasks = @()

# key value pair for the strings to match and the max count of matches before they are considered an issue
$keywords = @(,@())
$maxCounts = @(,@())


#### FUNCTION CALLS

LoadLogTailerConfig $logConfigPath ([ref]$logPaths) ([ref]$logFileMasks) ([ref]$keywords) ([ref]$maxCounts)

for ($i = 0; $i -lt $logPaths.Count; $i++)
{
    $tail = GetLogTail $numLinesToTail $logPaths[$i] $logFileMasks[$i]

    $tailIssueTable = CheckForKeywords $tail $keywords[$i] $maxCounts[$i]


}

}

# Loads in configuration data for the utility to use
function LoadLogTailerConfig($logConfigPath, [ref]$logPaths, [ref]$logFileMasks, [ref]$keywords, [ref]$maxCounts)
{
    Write-Debug "Loading config file data from $logConfigPath"

    [xml]$configData = Get-Content "C:\Testing\Configuration\config.xml"

    foreach ($log in $configData.Logs.Log) {

        $logPaths.Value += $log.FilePath
        $logFileMasks.Value += $log.FileMask

        $kwp = @()
        $kwc = @()

        foreach ($keywordSet in $log.Keywords.Keyword)
        {
            $kwp += $keywordSet.Pattern
            $kwc += $keywordSet.MaxMatches 
        }

        $keywords.Value += $kwp
        $maxCounts.Value += $kwc
    }
}

# Returns body text for email containing details on keywords in the log file and their frequency
function CheckForKeywords($tail, $keywords, $maxCounts)
{   
    $issuesFound = 0


    for ($i = 0; $i -lt $keywords.Count; $i++)
    {
        $keywordCount = ($tail | Select-String $keywords[$i] -AllMatches).Matches.Count

        Write-Debug $keywords.Count

        Write-Debug (("Match count for {0} : {1}" -f $keywords[$i], $keywordCount))

        if ($keywordCount -gt $maxCounts)
        {
            #do stuff
        }
    }

    return ""
}

Main

Much like you last question you need to declare your functions before you call them. CheckForKeywords needs to be before the line you call it from — Matt
– Matt, Commented Feb 3, 2015 at 13:35
just as in my last question that has already been done, I just simplified the code for the purposes of this question, I can assure you that the functions are declared and called correctly, it is merely the arrays that are behaving unexpectedly, I have edited for your peace of mind — Matthew Pigram
– Matthew Pigram, Commented Feb 3, 2015 at 22:48
Matthew Pigram, it's not the peace of mind. It's just it's easier for people to help you if they don't need to monkey around switching the order of lines of code to reproduce your issue. @matt — Andrew Savinykh
– Andrew Savinykh, Commented Feb 3, 2015 at 23:06
Could you please provide a) the definition of GetLogTail and b) sample of config.xml — Andrew Savinykh
– Andrew Savinykh, Commented Feb 3, 2015 at 23:11
@zespri GetLogTail is not necessary as it does not involve the variables in question. I would provide the config file however it would appear that applying the changes in your answer below got the desired result. — Matthew Pigram
– Matthew Pigram, Commented Feb 4, 2015 at 2:44

Andrew Savinykh · Accepted Answer · 2015-02-03 23:55:11Z

1

What you are doing is not a two dimensional array it's a nested array. By writing

$keywords = @(,@())
$maxCounts = @(,@())

you are creating an array with one element. This element is an array with zero elements. You don't need that. So change the above to:

$keywords = @()
$maxCounts = @()

Now when you do this:

$keywords.Value += $kwp
$maxCounts.Value += $kwc

powershell unravels the arrays on the right and concatinates element by element with arrays on the left. That's not what you want. So change this to

$keywords.Value += @(,$kwp)
$maxCounts.Value += @(,$kwc)

On a side note using by ref parameters is not idiomatic in powershell and it's not as easy to get help with that approach. I suggest changing your functions to pass the results via the pipeline, the powershell way, people who are going to support your script in future will appreciate that. You can model different type of values that you are wanting to return as properties on an object and return that object instead. Good luck.

answered Feb 3, 2015 at 23:55

Andrew Savinykh

26.7k20 gold badges110 silver badges168 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Matthew Pigram Over a year ago

this was the correct way to get it working. Thanks :)

Collectives™ on Stack Overflow

Powershell two dimensional array not working as expected

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related