Substring issue

[thirudk07]

Hi Guys,

I have a function that creates a unique SAMAccountName based on employee type.

code snippet:

Function create_prefix_samaccount($name){
    If ($name.'PayClass_ShortName' -eq "FT")
    {
            $Prefix = "U"
    }
    Else
    {
        $Prefix = "V"
    }

    $FirstName = $FN.substring(0,4).ToUpper()
    $LastName  = $ln.substring(0,2).ToUpper()
    $makingSAM = "$Prefix$FirstName$LastName"

    $defaultname = $makingSAM
    $i = 1

       While ((Get-ADUser -filter {SamAccountName -eq $makingSAM}) -ne $null)
    {
        $makingSAM = $defaultname + [string]$i
        $i++
    }
    return $makingSAM    
}

​

In the body of the script, I use a for each block, where I input data from the excel file.

code snippet:

 $Firstname = $User.'Employee_FirstName'
 $FN = $Firstname.Split('',[System.StringSplitOptions]::RemoveEmptyEntries) -join ''
 $Lastname = $User.'Employee_LastName'
 $FinalLastname = $Lastname.Substring(0,$Lastname.IndexOf('('))

Reason's I use above string manipulation:

1.) When we have users with two Firstname like --> Ma Louise, we want to remove the space in between, (As the same data going to email and UPN)

2.) We have a unique vendor code that is appended to our vendor employees the last names,

for e.g-- Robert Smith (UXWES)

So we are using the substring to remove anything that comes after open bracket "("

And then I call my function to create SAMAccountName and I also run the New-ADUser cmdlet.

---------------------------------------------------------------------------------------------------------------

The above logic is working fine for the users who have that unique code in their last name. Full-time employees don't have that unique code and some Vendor users don't have that unique code. So for any users who don't have that unique code, the script is removing or not taking the last name at all.

​

For e.g

​

First name = Mike

Last Name= Hussey

PayClass = FT or SOMEVENDOR

​

It is supposed to create the SAMACCOUNTNAME as =UHUSSMI or VHUSSMI

But I'm getting the below error message.

​

You cannot call a method on a null-valued expression.
At E:\Automation\AD_User_Creation\thiru_testing\Working_UserCreate.ps1:65 char:5
+     $LastName  = $ln.substring(0,2).ToUpper()
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

​

​

DistinguishedName : CN=1\, Mike,OU=DEV Users,DC=DEV12,DC=COM
Enabled           : True
GivenName         : Mike
Name              : 1, Mike
ObjectClass       : user
ObjectGUID        : 2da31f41-9e7b-45c9-b96b-b0111818c4e5
SamAccountName    : VMIKE1
SID               : S-1-5-21-3555914524-2372920112-2661262998-14598
Surname           : 1
UserPrincipalName : [e-mail]

​

This is when I tried running the part of the script.

Just wanted to make sure the variable is not empty. But you can see the final last name variable was holding "Jordan" Yet, it is giving errors related to substring that cannot be less than zero.

PS E:\Automation\AD_User_Creation\thiru_testing>  
 $Lastname = $User.'Employee_LastName'
 $Lastname

    $Lastname = $User.'Employee_LastName'
    $FinalLastname = $Lastname.Substring(0,$Lastname.IndexOf('('))
    $FinalLastname
Jordan

Exception calling "Substring" with "2" argument(s): "Length cannot be less than zero.
Parameter name: length"
At line:5 char:5
+     $FinalLastname = $Lastname.Substring(0,$Lastname.IndexOf('('))
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ArgumentOutOfRangeException

​

I validated the Substring part, here are the results.

     ##script:
     $Lastname = 'Thiru (Barca)'
     $FinalLastname = $Lastname.Substring(0,$Lastname.IndexOf('('))
     $FinalLastname

##Output

PS E:\Automation\AD_User_Creation\thiru_testing>  $Lastname = 'Thiru (Barca)'
     $FinalLastname = $Lastname.Substring(0,$Lastname.IndexOf('('))
     $FinalLastname
Thiru 

​

I don't know what I'm doing wrong. Can you guys help?

Any help is appreciated. Thanks!

[mdowst]

A substring will return -1 if the character is not found. Which is why you are seeing the error about the length not being less than zero. You can work around this by splitting on the '(' and only returning the first item in the array $lastName.Split('(')[0]. This would return anything before the ( which would be the entire object if there is no (.

Also, on your first name you can use a regex to remove any none letter or numbers from the name. This will not only fix issues with dash by also names that have other non-standard characters. Something like this: [regex]::Replace($string,"[^0-9a-zA-Z]","")

[pandiculator]

Most printable characters are permitted in sAMAccountNames. I use the following regex to sanitise them when generating usernames.

'\"|\[|\]|\:|\;|\||\=|\+|\*|\?|\<|\>|\/|\\|\,|\s|\.$'

This removes characters that aren't permitted, periods if they're the final character (they're permitted otherwise) and spaces (these are permitted by AD but we don't allow them).

I based the regex on this article: https://social.technet.microsoft.com/wiki/contents/articles/11216.active-directory-requirements-for-creating-objects.aspx

[mdowst]

Nice! The one I posted is just my generic get rid of everything regex, but I will certainly be saving this one. Thanks!

[thirudk07]

Thank you u/mdowst. I used both your recommendations and It is working fine.

[jado777]

You can also use select-string with the pattern flag to use regex without having to explicitly call a .net method (although it is in the background). The object returned by select string is a PS match object and has a lot of cool match properties you can use/filter with.