Powershell – Compare an element of an array with the previous element in PowerShell

log-filespowershell

Can someone describe a good pattern to compare $entry[X] to $entry[Y] to determine if they are the same? I'm trying to get readable summaries of my logs and don't want to spit out 400 identical lines.

foreach ($log in $logs) {

    $nm = $log.LogDisplayName

    $header = $log.LogDisplayName
    Write-Host $header
    Add-Content $output "$header Log Errors/Warnings, Past 48 Hours"

    $entries = $log.Entries | ? {$_.TimeWritten -gt ($(Get-Date).AddDays(-2)) -and (($_.EntryType -like "Error") -or ($_.EntryType -like "Warning"))}

    foreach ($entry in $entries) { 


        ***here is where I think I need to compare array elements***


    }


    out-string -inputobject $entries | add-content $output

Best Answer

To compare the current entry to the previous one:

$preventry = ""
$newarray = $()
foreach ($entry in $entries) {
    if ($entry -ne $preventry) { $newarray += @($entry) }
    $preventry = $entry
}

The resulting array $newarray contains all the contents of $entries but with the adjacent duplicates removed.

Related Solutions

PowerShell – Literal Escape Character

From help about_quoting_rules

To make double-quotation marks appear in a string, enclose the entire string in single quotation marks. For example:
'As they say, "live and learn."'
The output from this command is:
As they say, "live and learn."
You can also enclose a single-quoted string in a double-quoted string. For example:
"As they say, 'live and learn.'"
The output from this command is:
As they say, 'live and learn.'
To force Windows PowerShell to interpret a double quotation mark literally, use a backtick character. This prevents Windows PowerShell from interpreting the quotation mark as a string delimiter. For example:
"Use a quotation mark (`") to begin a string."
The output from this command is:
Use a quotation mark (") to begin a string.
Because the contents of single-quoted strings are interpreted literally, you cannot use the backtick character to force a literal character interpretation in a single-quoted string.

The use of the backtick character to escape other quotation marks in single quoted strings is not supported in recent versions of PowerShell. In earlier versions of PowerShell the backtick escape character could be used to escape a double quotation mark character within a single quoted string as detailed in the help about_quoting document that is available in those versions of PowerShell.

Windows – Powershell array robocopy

$serverNames = ("serverA","serverB", "serverC")
foreach ($server in $serverNames ) 
{ 
    ROBOCOPY.exe C:\Websites\ \\$server\C$\Websites\ /MIR
}

Make sure that Robocopy is in the path. Remeber that the current working is not part of the path in PS so if robocopy is in the current working directory, prepend it with .\ (.\Robocopy.exe...). For executeables you need to specify the .exe on the file name.

If your list of servers is not too long you can one line it too (this one assumes robocopy is in the current working dir):

("serverA","serverB", "serverC") | %{.\Robocopy.exe C:\Websites\ \\$_\Websites\ /MIR}

Best Answer

Related Solutions

PowerShell – Literal Escape Character

Windows – Powershell array robocopy

Related Topic