PowerShell Isn't Parsing Data as Expected // Basic PowerShell Operator Question - powershell

I have a pretty nooby question regarding the proper usage of certain operators.
I am writing a script that pulls data out of a CSV. The script asks the user to enter a location # and then is supposed to output the IP of their server.
The script works as expected except on rows where the location number also has other text in it like numbers or special characters.
Here is an example CSV to illustrate my problem:
Loc#,State,Server IP
1,NY,10.0.0.1
2,CA,10.0.0.2
3,WA,10.0.0.3
4 (inp),KY,10.0.0.4
My script looks something like this:
$CSV = import-csv C:\users\Self\MyProject.csv
$location = read-host "enter the location #"
foreach( $row in $CSV){
if($row.loc# -eq $location)
{
write-host $row.'Server IP'
}
Now, this script works as expected unless the user chooses location 4. If the users chooses location 4, then the $location variable is left blank.
Ok, this makes a little bit of sense since I'm using the -eq operator. But even if I use the -contains operator I get the same results.
Here is another way of showing my problem:
$number = "10 ten"
if ($number -contains "10"){ (Write-Host "true")} else{ write-host "false"}
false
Now, why isn't the output showing as "true" since that $number variable does indeed contain "10"?
Any help is much appreciated,
Thanks

As it seems, Location can have a random value and not only digits, normally you could use -match as Mahmoud Moawad pointed out in his comment, however this could also bring you problems since there is no specific pattern you can follow there is also no clear way of how you can filter the specific value. What I would personally do is give the user a list where he can choose the Location by Index:
$csv = Import-Csv C:\users\Self\MyProject.csv
$csv.foreach({
begin
{
'- Choose a location:'
$i = 0
$map = #{}
}
process
{
$map[(++$i)] = $_
"[$i] - {0}" -f $_.'Loc#'
}
})
$question = { Read-Host 'Index' }
while($true)
{
$index = (& $question) -as [int]
if($index -ge 1 -and $index -le $csv.Count)
{
break
}
'Input must be between 1 and {0}!!' -f $csv.Count
}
$map[$index].'Server IP'
As for why -contains is not showing you $true on your condition, the Containment Operators will look for an exact match of an element:
'10 ten' -contains '10' # => False
'10 ten' -contains '10 ten' # => True
'9 nine', '10 ten' -contains '10 ten' # => True

Related

Nested if and for loop errors

would any of you be able to help me with the below code
$pcname = "jwang"
#We set $test as a string to be called later
$test = get-adcomputer -filter "name -like '$pcname'" | select -ExpandProperty name
#We define a null string to test our IF statement
$nothing = $null
$number = 1
if ($test -ne $null) {
Write-Host "$pcname is currently in use"
for($number = 1; ($test = get-adcomputer -filter "name -like '$pcname + $number'" | select -ExpandProperty name) -ne $null; $number++ ){
Write-Host $pcname + $number
}
}
else {
Write-host "AD lookup complete, new PC name will be $pcname"
}
The IF statement works correctly, but the trouble starts when I add the nested FOR loop.
The end goal is to have AD tell me if the name is available or not.
Right now in AD there is
JWANG
JWANG1
JWANG2
JWANG3
JWANG4
I want the for loop to eventuelly tell me that "JWANG5" is available, any help is appreciated, thank you
The immediate problem with your code is that $pcname + $number - an expression - isn't enclosed in $(...), the subexpression operator inside your expandable (double-quoted) string ("...").
Therefore, use $($pcname + $number) or, relying on mere string interpolation, $pcname$number
An aside re testing for $null:
It is advisable to make $null the LHS for reliably null testing (if ($null -ne $test)), because on the RHS it acts as a filter if the LHS happens to be an array - see about_Comparison_Operators.
However, often - such as when objects are being returned from a command, you can simply use implicit to-Boolean conversion (if ($test)) - see the bottom section of this answer for the complete rules.
Taking a step back:
Querying AD multiple times is inefficient, and since you're already using the -like operator, you can use it with a wildcard pattern to find all matching names at once:
$pcname = 'jwang'
# Note the use of "*" to match all names that *start with* $pcname
$names = get-adcomputer -filter "name -like '$pcname*'" | select -ExpandProperty name
if ($names) { # at least one name found
Write-Host "$pcname is currently in use"
# Find the highest number embedded in the matching names.
$seqNums = [int[]] ($names -replace '\D')
# The new sequence number is the next number following the currently highest.
$nextSeqNum = 1 + [Linq.Enumerable]::Max($seqNums)
# Form the new name and output it.
$pcname + $nextSeqNum
}
else {
Write-host "AD lookup complete, new PC name will be $pcname"
}

If not empty jump to somewhere in PS

Hello and good morning(:
I'm looking to see if I'm able to jump to somewhere in PS without wrapping it in a ScriptBlock; hell, I'd even be okay with that but, I'm just unsure on how to go about it.
What I'm trying to do is: add a Parameter Set to a function and if something is supplied to the parameter -GrpSelec(I know imma change it), then just skip the rest of the script and go to my $swap variable to perform the switch.
$Group1 = #("1st Group", "2nd Group")
$Group2 = #("3rd Group", "4th Group")
Function Test-Group{
param(
[ValidateSet("Group1","group2")]
[array]$GrpSelec)
if($GrpSelec){ &$swap }
$AllGroups = #("Group1", "Group2")
for($i=0; $i -lt $AllGroups.Count; $i++){
Write-Host "$($i): $($AllGroups[$i])"}
$GrpSelec = Read-Host -Prompt "Select Group(s)"
$GrpSelec = $GrpSelec -split " "
$swap = Switch -Exact ($GrpSelec){
{1 -or "Group1"} {"$Group1"}
{2 -or "Group2"} {"$Group2"}
}
Foreach($Group in $swap){
"$Group"}
}
Is something like this even possible?
I've googled a couple of similar questions which point to the invocation operator &(as shown above), and/or, a foreach which is definitely not the same lol.
take it easy on me, im just experimenting(:
How about a simple if statement?
function Test-Group {
param(
[string[]]$GrpSelec
)
if(!$PSBoundParameters.ContainsKey('GrpSelect')){
# no argument was passed to -GrpSelec,
# populate $GrpSelec in here before proceeding with the rest of the script
}
# Now that $GrpSelec has been populated, let's do the work
$swap = Switch -Exact ($GrpSelec){
{1 -or "Group1"} {"$Group1"}
{2 -or "Group2"} {"$Group2"}
}
# rest of function
}

Powershell - combine switch statement and loop

I have a piece of code presented below, it takes values from a json file. This is a array of string --> $Json.Names. I would like to avoid duplicate lines like --> $Json.Names[0].Name {$Json.Names[0].Name; break}. Second case is that Array $Json.Names could have different length, array can have 6 and more or less elements. I want to make this switch statement more elastic. I tried to use for loop and while loop, but in this case these loops doesn't help me. Is there any clever method to make this code more sophisticated/elastic and avoid duplicate mentioned code lines$Json.Names[0].Name {$Json.Names[0].Name; break}
$Json = Get-Content "$path" | out-string | ConvertFrom-Json
$Name = switch ($Member) {
$Json.Names[0].Name {$Json.Names[0].Name; break}
$Json.Names[1].Name {$Json.Names[1].Name; break}
$Json.Names[2].Name {$Json.Names[2].Name; break}
$Json.Names[3].Name {$Json.Names[3].Name; break}
$Json.Names[4].Name {$Json.Names[4].Name; break}
$Json.Names[5].Name {$Json.Names[5].Name; break}
$Json.Names[6].Name {$Json.Names[6].Name; break}
default {"Unknown Name"}
}
Assuming this structure:
$json = [pscustomobject]#{names = [pscustomobject]#{name ='joe'},
[pscustomobject]#{name ='john'},
[pscustomobject]#{name ='james'}}
Assuming $member is a single name, you can say
$name = $json.names.name -eq $member # an array of one
$name would be a null array if there's no match.
if (! $name) { $name = 'Unknown Name' }
Or, in the language of Powershell 7 preview 5:
$name ??= 'Unknown Name'
You also may want to make a hashtable of the names.
You can take advantage of property enumeration and simplify your code pretty significantly:
# define our default
$Name = "Unknown Name"
# define the list of names
$Json = Get-Content "$path" | ConvertFrom-Json
$Names = $Json.Names.Name
# update $Name if applicable
if($Names -contains $member){
$Name = $member
}

Printing useful variable values in powershell (in particular, involving $null/empty string)

If I have:
$a=$null
$b=''
$c=#($null,$null)
$d='foo'
write-host $a
write-host $b
write-host $c
write-host $d
the output is
foo
I'd really like to be able to easily get output that shows the variable values, e.g.,
$Null
''
#($Null,$Null)
'foo'
I can write a function to do this, but I'm guessing/hoping there's something built-in that I'm missing. Is there, or does everyone just roll their own function for something like this?
At the moment the quickest thing I've come up with is running a value through ConvertTo-Json before printing it. It doesn't handle a plain $null, but it shows me the other values nicely.
What you're looking for is similar to Ruby's .inspect method. It's something I always loved in Ruby and do miss in PowerShell/.Net.
Unfortunately there is no such thing to my knowledge, so you will somewhat have to roll your own.
The closest you get in .Net is the .ToString() method that, at a minimum, just displays the object type (it's inherited from [System.Object]).
So you're going to have to do some checking on your own. Let's talk about the edge case checks.
Arrays
You should check if you're dealing with an array first, because PowerShell often unrolls arrays and coalesces objects for you so if you start doing other checks you may not handle them correctly.
To check that you have an array:
$obj -is [array]
1 -is [array] # false
1,2,3 -is [array] # true
,1 -is [array] #true
In the case of an array, you'll have to iterate it if you want to properly serialize its elements as well. This is basically the part where your function will end up being recursive.
function Format-MyObject {
param(
$obj
)
if ($obj -is [array]) {
# initial array display, like "#(" or "["
foreach ($o in $obj) {
Format-MyObject $obj
}
# closing array display, like ")" or "]"
}
}
Nulls
Simply check if it's equal to $null:
$obj -eq $null
Strings
You can first test that you're dealing with a string by using -is [string].
For empty, you can compare the string to an empty string, or better, to [string]::Empty. You can also use the .IsNullOrEmpty() method, but only if you've already ruled out a null value (or checked that it is indeed a string):
if ($obj -is [string) {
# pick one
if ([string]::IsNullOrEmpty($obj)) {
# display empty string
}
if ($obj -eq [string]::Empty) {
# display empty string
}
if ($obj -eq "") { # this has no advantage over the previous test
# display empty string
}
}
Alternative
You could use the built-in XML serialization, then parse the XML to get the values out of it.
It's work (enough that I'm not going to do it in an SO answer), but it removes a lot of potential human error, and sort of future-proofs the approach.
The basic idea:
$serialized = [System.Management.Automation.PSSerializer]::Serialize($obj) -as [xml]
Now, use the built in XML methods to parse it and pull out what you need. You still need to convert some stuff to other stuff to display the way you want (like interpreting <nil /> and the list of types to properly display arrays and such), but I like leaving the actual serialization to an official component.
Quick example:
[System.Management.Automation.PSSerializer]::Serialize(#(
$null,
1,
'string',
#(
'start of nested array',
$null,
'2 empty strings next',
'',
([string]::Empty)
)
)
)
And the output:
<Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04">
<Obj RefId="0">
<TN RefId="0">
<T>System.Object[]</T>
<T>System.Array</T>
<T>System.Object</T>
</TN>
<LST>
<Nil />
<I32>1</I32>
<S>string</S>
<Obj RefId="1">
<TNRef RefId="0" />
<LST>
<S>start of nested array</S>
<Nil />
<S>2 empty strings next</S>
<S></S>
<S></S>
</LST>
</Obj>
</LST>
</Obj>
</Objs>
I shared two functions that reveal PowerShell values (including the empty $Null's, empty arrays etc.) further than the usually do:
One that the serializes the PowerShell objects to a PowerShell
Object Notation (PSON)
which ultimate goal is to be able to reverse everything with the
standard command Invoke-Expression and parse it back to a
PowerShell object.
The other is the ConvertTo-Text (alias CText) function that I used in
my Log-Entry
framework. note the
specific line: Log "Several examples that usually aren't displayed
by Write-Host:" $NotSet #() #(#()) #(#(), #()) #($Null) that I wrote
in the example.
Function Global:ConvertTo-Text1([Alias("Value")]$O, [Int]$Depth = 9, [Switch]$Type, [Switch]$Expand, [Int]$Strip = -1, [String]$Prefix, [Int]$i) {
Function Iterate($Value, [String]$Prefix, [Int]$i = $i + 1) {ConvertTo-Text $Value -Depth:$Depth -Strip:$Strip -Type:$Type -Expand:$Expand -Prefix:$Prefix -i:$i}
$NewLine, $Space = If ($Expand) {"`r`n", ("`t" * $i)} Else{"", ""}
If ($O -eq $Null) {$V = '$Null'} Else {
$V = If ($O -is "Boolean") {"`$$O"}
ElseIf ($O -is "String") {If ($Strip -ge 0) {'"' + (($O -Replace "[\s]+", " ") -Replace "(?<=[\s\S]{$Strip})[\s\S]+", "...") + '"'} Else {"""$O"""}}
ElseIf ($O -is "DateTime") {$O.ToString("yyyy-MM-dd HH:mm:ss")}
ElseIf ($O -is "ValueType" -or ($O.Value.GetTypeCode -and $O.ToString.OverloadDefinitions)) {$O.ToString()}
ElseIf ($O -is "Xml") {(#(Select-XML -XML $O *) -Join "$NewLine$Space") + $NewLine}
ElseIf ($i -gt $Depth) {$Type = $True; "..."}
ElseIf ($O -is "Array") {"#(", #(&{For ($_ = 0; $_ -lt $O.Count; $_++) {Iterate $O[$_]}}), ")"}
ElseIf ($O.GetEnumerator.OverloadDefinitions) {"#{", (#(ForEach($_ in $O.Keys) {Iterate $O.$_ "$_ = "}) -Join "; "), "}"}
ElseIf ($O.PSObject.Properties -and !$O.value.GetTypeCode) {"{", (#(ForEach($_ in $O.PSObject.Properties | Select -Exp Name) {Iterate $O.$_ "$_`: "}) -Join "; "), "}"}
Else {$Type = $True; "?"}}
If ($Type) {$Prefix += "[" + $(Try {$O.GetType()} Catch {$Error.Remove($Error[0]); "$Var.PSTypeNames[0]"}).ToString().Split(".")[-1] + "]"}
"$Space$Prefix" + $(If ($V -is "Array") {$V[0] + $(If ($V[1]) {$NewLine + ($V[1] -Join ", $NewLine") + "$NewLine$Space"} Else {""}) + $V[2]} Else {$V})
}; Set-Alias CText ConvertTo-Text -Scope:Global -Description "Convert value to readable text"
ConvertTo-Text
The ConvertTo-Text function (Alias CText) recursively converts PowerShell object to readable text this includes hash tables, custom objects and revealing type details (like $Null vs an empty string).
Syntax
ConvertTo-Text [<Object>] [[-Depth] <int>] [[-Strip] <int>] <string>] [-Expand] [-Type]
Parameters
<Object>
The object (position 0) that should be converted a readable value.
-⁠Depth <int>
The maximal number of recursive iterations to reveal embedded objects.
The default depth for ConvertTo-Text is 9.
-Strip <int>
Truncates strings at the given length and removes redundant white space characters if the value supplied is equal or larger than 0. Set -Strip -1 prevents truncating and the removal of with space characters.
The default value for ConvertTo-Text is -1.
-Expand
Expands embedded objects over multiple lines for better readability.
-Type
Explicitly reveals the type of the object by adding [<Type>] in front of the objects.
Note: the parameter $Prefix is for internal use.
Examples
The following command returns a string that describes the object contained by the $var variable:
ConvertTo-Text $Var
The following command returns a string containing the hash table as shown in the example (rather then System.Collections.DictionaryEntry...):
ConvertTo-Text #{one = 1; two = 2; three = 3}
The following command reveals values (as e.g. $Null) that are usually not displayed by PowerShell:
ConvertTo-Text #{Null = $Null; EmptyString = ""; EmptyArray = #(); ArrayWithNull = #($Null); DoubleEmptyArray = #(#(), #())} -Expand
The following command returns a string revealing the WinNT User object up to a level of 5 deep and expands the embedded object over multiple lines:
ConvertTo-Text ([ADSI]"WinNT://./$Env:Username") -Depth 5 -Expand
A quick self-rolled option good for some datatypes.
function Format-MyObject {
param(
$obj
)
#equality comparison order is important due to array -eq overloading
if ($null -eq $obj)
{
return 'null'
}
#Specify depth because the default is 2, because powershell
return ConvertTo-Json -Depth 100 $obj
}

Reading strings from text files using switch -regex returns null element

Question:
The intention of my script is to filter out the name and phone number from both text files and add them into a hash table with the name being the key and the phone number being the value.
The problem I am facing is
$name = $_.Current is returning $null, as a result of which my hash is not getting populated.
Can someone tell me what the issue is?
Contents of File1.txt:
Lori
234 east 2nd street
Raleigh nc 12345
9199617621
lori#hotmail.com
=================
Contents of File2.txt:
Robert
2531 10th Avenue
Seattle WA 93413
2068869421
robert#hotmail.com
Sample Code:
$hash = #{}
Switch -regex (Get-content -Path C:\Users\svats\Desktop\Fil*.txt)
{
'^[a-z]+$' { $name = $_.current}
'^\d{10}' {
$phone = $_.current
$hash.Add($name,$phone)
$name=$phone=$null
}
default
{
write-host "Nothing matched"
}
}
$hash
Remove the current property reference from $_:
$hash = #{}
Switch -regex (Get-content -Path C:\Users\svats\Desktop\Fil*.txt)
{
'^[a-z]+$' {
$name = $_
}
'^\d{10}' {
$phone = $_
$hash.Add($name, $phone)
$name = $phone = $null
}
default {
Write-Host "Nothing matched"
}
}
$hash
Mathias R. Jessen's helpful answer explains your problem and offers an effective solution:
it is automatic variable $_ / $PSItem itself that contains the current input object (whatever its type is - what properties $_ / $PSItem has therefore depends on the input object's specific type).
Aside from that, there's potential for making the code both less verbose and more efficient:
# Initialize the output hashtable.
$hash = #{}
# Create the regex that will be used on each input file's content.
# (?...) sets options: i ... case-insensitive; m ... ^ and $ match
# the beginning and end of every *line*.
$re = [regex] '(?im)^([a-z]+|\d{10})$'
# Loop over each input file's content (as a whole, thanks to -Raw).
Get-Content -Raw File*.txt | foreach {
# Look for name and phone number.
$matchColl = $re.Matches($_)
if ($matchColl.Count -eq 2) { # Both found, add hashtable entry.
$hash.Add($matchColl.Value[0], $matchColl.Value[1])
} else {
Write-Host "Nothing matched."
}
}
# Output the resulting hashtable.
$hash
A note on the construction of the .NET [System.Text.RegularExpressions.Regex] object (or [regex] for short), [regex] '(?im)^([a-z]+|\d{10})$':
Embedding matching options IgnoreCase and Multiline as inline options i and m directly in the regex string ((?im) is convenient, in that it allows using simple cast syntax ([regex] ...) to construct the regular-expression .NET object.
However, this syntax may be obscure and, furthermore, not all matching options are available in inline form, so here's the more verbose, but easier-to-read equivalent:
$re = New-Object regex -ArgumentList '^([a-z]+|\d{10})$', 'IgnoreCase, Multiline'
Note that the two options must be specified comma-separated, as a single string, which PowerShell translates into the bit-OR-ed values of the corresponding enumeration values.
other solution, use convertfrom-string
$template=#'
{name*:Lori}
{street:234 east 2nd street}
{city:Raleigh nc 12345}
{phone:9199617621}
{mail:lori#hotmail.com}
{name*:Robert}
{street:2531 10th Avenue}
{city:Seattle WA 93413}
{phone:2068869421}
{mail:robert#hotmail.com}
{name*:Robert}
{street:2531 Avenue}
{city:Seattle WA 93413}
{phone:2068869421}
{mail:robert#hotmail.com}
'#
Get-Content -Path "c:\temp\file*.txt" | ConvertFrom-String -TemplateContent $template | select name, phone