I want to compare two Lists of Arrays and to display the Delta in a third array:
$ListOfVMs
$ListOfRunningVMs
$StoppedVMs = $ListOfVMs | { Where-Object $_.Name -notcontains $ListOfVMs.Name }
This Filter delivers still the complete Content of $ListOfVMs and not only the Delta. What I am doing wrong?
You may do the following:
$StoppedVMs = $ListOfVMs | Where-Object Name -notin $ListOfRunningVMs.Name
You need to pipe to Where-Object. Where-Object is what contains the script block (if you need to use it). You are also not comparing both lists here as you only reference $ListOfVMs.
Since you are comparing a single item against a collection, you will want to use -notin if the single item is on the left-hand side (LHS). -notcontains would be used if the collection is on the LHS.
Related
I have 2 Arrays $UsersGroup and $UsersActive, i need to find where in $UsersActive i have a line with SamAccountName and the ObjectGUID .
$UsersGroup =
SamAccountName ObjectGUID
-------------- ----------
XXXX00XX 0031e949-9120-4df1-bddb-98067a141448
XXXX01XX 0031e949-9120-4df1-bdgb-99067a141448
XXXX02XX 0031e949-9120-4df1-bdab-97067a141448
and without headers
$UsersActive =
fcb483fa146b
fcb515739a2f
fcb82f1ef74c
fcc5ee8b8722
fcd3f1f471c2
fceb26a598a3
fd0b14cecd0e
98067a141448
I need to have the match user from $UsersActive to $UserGroup.Object like that
$UsersGroup | ForEach-Object {if($_.ObjectGUID -contains $UsersActive) {$_}}
But i don't get the result like that :
XXXX00XX 0031e949-9120-4df1-bddb-98067a141448
Can some one help me , thanks !
-contains is a collection containment operator, testing for the exact occurrence of the right-hand side argument in the left-hand side argument.
To test for the presence of a substring in a string, use the -like wildcard string comparison operator:
$UsersGroup | Where-Object {
$guid = $_.ObjectGUID
$UsersActive.Where({$guid -like "*$_*"}, 'First')
}
Each group entry will now be tested against every $UsersActive value until a match is found (causing Where-Object to pass the object through) or no match is found (causing Where-Object to filter out the object)
If I understand you correctly, using compare-object... This has only one match. Compare-object can be slow for large lists.
$usersgroup =
'SamAccountName,ObjectGUID
XXXX00XX,0031e949-9120-4df1-bddb-98067a141448
XXXX01XX,0031e949-9120-4df1-bdgb-99067a141448
XXXX02XX,0031e949-9120-4df1-bdab-97067a141448' | convertfrom-csv
$usersactive = -split
'fcb483fa146b
fcb515739a2f
fcb82f1ef74c
fcc5ee8b8722
fcd3f1f471c2
fceb26a598a3
fd0b14cecd0e
98067a141448'
compare ($usersgroup.objectguid -replace '.*-') $usersactive -IncludeEqual |
? sideindicator -eq '==' # order doesn't matter
InputObject SideIndicator
----------- -------------
98067a141448 ==
To offer an alternative solution:
As Mathias states in his answer, the -contains operator and its operands-reversed counterpart, -in, only perform equality comparison of a single comparison value against the elements of a collection (array).
As an aside: Given that $_.ObjectGUID is the scalar (single object) and $UsersActive the collection (array) to search in, you would have needed to use -in, not -contains ($_.ObjectGUID -in $UsersActive)
Unfortunately, as of version 7.3.2, PowerShell's pattern-matching operators, -like (with wildcard expressions) and -match (with regexes), do not support matching against multiple (an array of) patterns.
However, since you're looking to match a literal substring of each .ObjectGUID value, you can use -in if you extract that relevant substring first and use it as the comparison value:
# -> Object whose GUID is '0031e949-9120-4df1-bddb-98067a141448'
$usersGroup | Where-Object { ($_.ObjectGUID -split '-')[-1] -in $usersActive }
Note how the -split operator is used to split the GUID into tokens by -, with [-1] returning the last token, which -in then looks for by equality comparison in the $UsersActive array.
As an aside:
Allowing multiple patterns as the RHS of -like and -match - so as to return $true if any of them match - would be a helpful future improvement.
GitHub issue #2132 asks for just that.
I have two array's, one contains multiple columns from a CSV file read in, and the other just contains server names, both type string. For this comparison, I plan on only using the name column from the CSV file. I don't want to use -compare because I want to still be able to use all CSV columns with the results. Here is an example of data from each array.
csvFile.Name:
linu40944
windo2094
windo4556
compareFile:
linu40944
windo2094
linu24455
As you can see, they contain similar server names, except $csvFile.Name contains 25,000+ records, and $compareFile contains only 3,500.
I've tried:
foreach ($server in $compareFile) {
if ($csvFile.Name -like $server) {
$count++
}
}
Every time I run this, it takes forever to run, and results in $count having a value in the millions when it should be roughly 3,000. I've tried different variations of -match, -eq, etc. where -like is. Also note that my end goal is to do something else where $count is, but for now I'm just trying to make sure it is outputting as much as it should, which it is not.
Am I doing something wrong here? Am I using the wrong formatting?
One possible thought given the size of your data.
Create a hashtable (dictionary) for every name in the first/larger file. Name is the Key. Value is 0 for each.
For each name in your second/smaller/compare file, add 1 to the value in your hashtable IF it exists. If it does not exist, what is your plan???
Afterwards, you can dump all keys and values and see which ones are 0, 1, or >1 which may or may not be of value to you.
If you need help with this code, I may be able to edit my answer. Since you are new, to StackOverflow, perhaps you want to try this first yourself.
Build custom objects from $compareFile (so that you can compare the same property), then use Compare-Object with the parameter -PassThru for the comparison. Discriminate the results using the SideIndicator.
$ref = $compareFile | ForEach-Object {
New-Object -Type PSObject -Property #{
'Name' = $_
}
}
Compare-Object $csvFile $ref -Property Name -PassThru | Where-Object {
$_.SideIndicator -eq '<='
} | Select-Object -Property * -Exclude SideIndicator
The trailing Select-Object removes the additional property SideIndicator that Compare-Object adds to the result.
What's the best way to rewrite the following powershell code that compares a list of two files, ensuring they have the same (or greater) file count, and that the second list contains every file in the first list:
$noNewFiles = $NewFiles.Count -ge $OldFiles.Count
foreach ($oldFile in $OldFiles){
if (!$NewFiles.Contains($oldFile)) {
return $false
}
}
PSv3+ syntax (? is a built-in alias for Where-Object cmdlet):
(Compare-Object $NewFiles $OldFiles | ? SideIndicator -eq '=>').Count -eq 0
More efficient PSv4+ alternative, using the Where() method (as suggested by Brian (the OP) himself):
(Compare-Object $NewFiles $OldFiles).Where-Object({ $_.SideIndicator -eq '=>' }).Count -eq 0
By default, Compare-Object only returns differences between two sets and outputs objects whose .SideIndicator property indicates the set that an element is unique to:
Since string value => indicates an element that is unique to the 2nd set (RHS), we can filter the differences down to elements unique to the 2nd set, so if their count is 0, the implication is that there are no elements unique to the 2nd set.
Side note:
How "sameness" (equality) is determined depends on the data type of the elements.
A pitfall is that instances of reference types are compared by their .ToString() values, which can result in disparate objects being considered equal. For instance, Compare-Object #{ one=1 } #{ two=2 } produces no output.
I have a CSV of devices that are missing security updates along with the date the update was released and kb number.
devicename,date,kb
Desktop1,9/12/17,KB4011055
Desktop1,9/12/17,KB4038866
Desktop2,9/12/17,KB4011055
Desktop2,6/13/17,KB3203467
I am trying to compile a list of devices that are missing updates that have been released in the past 30 days but exclude devices that are also missing older updates. So in the example above, the only device I want is Desktop 1.
I know I could do something like this to see devices that are under that 30 day window but that would still include devices that have other entries which are greater than 30 days.
$AllDevices | Where-Object {[datetime]$_.date_released -gt ((get-date).adddays(-30))}
I was thinking I could use Group-Object devicename to group all the devices together but I'm not sure how to check the dates from there.
Any ideas?
The assumption is that $AllDevices was assigned the output from something like
Import-Csv c:\path\to\some.csv and that PSv3+ is used.
$AllDevices | Group-Object devicename | Where-Object {
-not ([datetime[]] $_.Group.date -le (Get-Date).AddDays(-30))
} | Select-Object #{ l='devicename'; e='Name' }, #{ l='kbs'; e={ $_.Group.kb } }
With the sample input, this yields:
devicename kbs
---------- ---
Desktop1 {KB4011055, KB4038866}
Explanation:
Group-Object devicename groups all input objects by device name, which outputs a collection of [Microsoft.PowerShell.Commands.GroupInfo] instances each representing all input objects sharing a given device name (e.g., Desktop1) - see Get-Help Group-Object.
The Where-Object call is then used to weed out groups that contain objects whose date is older than 30 days.
[datetime[]] $_.Group.date creates an array of date-time objects [datetime[]] from the date-time strings (.date) of every member of the group $_.Group.
Note that $_.Group is the collection of input objects that make up the group, and even though .date is applied directly to $_.Group, the .date property is accessed on each collection member and the results are collected in an array - this handy shortcut syntax is called member-access enumeration and was introduced in PSv3.
-le (Get-Date).AddDays(-30) filters that array to only return members whose dates are older than 30 days; note that -le applied to an array-valued LHS returns a filtered subarray, not a Boolean.
-not negates the result of the -le comparison, which forces interpretation of the filtered array as a Boolean, which evaluates to $False if the array is empty, and $True otherwise; in other words: if one or more group members have dates older than 30 days, the -le comparison evaluates to $True as a Boolean, which -not negates.
This results in groups (and therfore devices) containing at least 1 older-than-30-days date getting removed from further pipeline processing.
Select-Object then receives only those group objects whose members all have dates that fall within the last 30 days, and uses calculated properties (via hashtable literals (#{...}) with standardized entries) to construct the output objects:
A group object's .Name property contains the value of the grouping property/ies passed to Group-Object, which in this case is the input objects' devicename property; #{ l='devicename'; e='Name' } simply renames the .Name property back to devicename.
#{ l='kbs'; e={ $_.Group.kb } } then constructs a kbs property that contains the array of kb values from the members of each group, retrieved by member-access enumeration via a script block { ... }
Note that Select-Object outputs [pscustomobject] instances containing only the explicitly defined properties; in this case, devicename and kbs.
I propose other solution:
import-csv "C:\temp\test.csv" |
select *, #{N="Date";E={[DateTime]$_.Date}} -ExcludeProperty "Date" |
group devicename |
%{
if (($_.Group | where Date -le (Get-Date).AddDays(-30)).Count -eq 0)
{
$LastUpdate=$_.Group | sort Date, kb -Descending | select -First 1
[pscustomobject]#{
DeviceName=$LastUpdate.DeviceName
DateLastUpdate=$LastUpdate.Date
LastUpdate=$LastUpdate.Kb
UpdateList=$_.Group.Kb -join ', '
Group=$_.Group
}
}
}
I have script which retrieves data from a web service in XML format. Certain elements can be there - or not - and can contain one or more sub elements. Therfore I retrieve the value with this:
$uid = $changeRecord.newAttrs | Where{$_.name -eq 'uid'} | Select -ExpandProperty Values | select -Index 0
This works fine. Mostly there is only one sub element in the <values> part of the answer and even if not, I am only interested in the first one. However, the last part | select -Index 0 produces silent warnings into the Windows Event Log (see also here ) if there is only one element within <values>. Therefore I would like to get rid of the error.
So I am looking for a way to achieve the same behaviour without it throwings errors - and possible not just put try-catch around.
Thanks!
// Update: As discussed below, the answers presented so far do not solve the issue. The closest by now is
([array]($changeRecord.newAttrs | Where{$_.name -eq 'uid'} | Select -ExpandProperty Values))[0]
This, however, fails with an error if the array does not contain any elements. Any idea if this can be handled as well within one line?
Have you tried this: Select-Object -First 1 ?
$uid = $changeRecord.newAttrs |
Where-Object {$_.name -eq 'uid'} |
Select-Object -ExpandProperty Values |
Select-Object -First 1
Select -Index n is only meant to be used on arrays as it will explicitly select from that index in the array. Therefore you will have issues when doing it on a single object. Select -First n will get you n number of objects off the pipeline.
All that said, when I am calling a command and the results may either be a single item or an array of items, I generally declare the variable as an array or cast the value as an array and then even if I get a single object back from the command it will be stored in an array. That way no matter what gets returned, I am treating it the same way. So in your case:
$uid = [array]($changeRecord.newAttrs | Where{$_.name -eq 'uid'} | Select -ExpandProperty Values) | select -Index 0
So, I finally found a solution which is probably fine for me:
$valueArray = [array]($changeRecord.newAttrs | Where{$_.name -eq 'uid'} | Select -ExpandProperty Values)
if(($valueArray -ne $null) -and ($valueArray.Count -gt 0))
{
$value = $valueArray.GetValue(0)
}
else
{
$value = "null..."
}
I put the whole thing into an array first and then check if the array contains any elements. Only if so, I get the first value.
Thanks for everybodys help!