If Else not working as expected

Hi Team,
I posted the same post 40 min ago, still its not showing so posted it again. If you found the previous post, you can ignore ny one.

I am going to post an if else issue that I can’t identify why this is happen.
Source File
Code that I write

$tar1=(Select-String -Pattern accounts -Path C:\type.txt).line if ($tar1::isemptyornull) {
'Err.. Required data not found'

} else {

$targ1=(Select-String -Pattern accounts, performing, "done test list operation" -Path C:\type.txt).line.trim()

}

“Following is the value”
$tar1

Please note, above quote is a part of main script, only this part is not working as expected.

The Story
From the attached link, you will get a file having some text. I want to pickup only specific text from that file, which is
“accounts”. So I write the script like that. The file is located at C drive of my system. You can modify the codes as per your requirement.

Case 1: I want, if the string (“accounts”) available, then the line will be captured along with 2 more pattern(defined under else) and will be stored on $tar1 through $targ1.

Case 2: If the string will no be available then $tar1 will hold the pre defined value ‘Err… Required data not found’.

Problem: If accounts string exists, then it works perfectly. But if you remove the accounts string from the source file, Its not
working as defined. Yes, if you add -not switch if (-not $tar1::isemptyornull) then it works again.

Can you please guide me, what is the issue.

Regards,
Roy.

I think you mean this (static method of string type)?

if ( [string]::IsNullOrEmpty($tar1) ) { 

although this should work:

if ( ! $tar1 ) {   # EDIT

Yep, that’s it. The :: operator is only valid with static classes and methods, so you can only call them from the type accelerator themselves. However, if you want the ::IsNullOrEmpty() effect with that syntax, you should use:

if (-not $string) {}

To clarify the alternative js mentions, both $null and “” (empty string) values will be automatically converted to the boolean value false, which you can see if you do so manually:

[bool]$null
[bool]""

This allows you to effectively perform the “null or empty” check without bothering to invoke a specific method. I find it helps me make sense of that if statement if I think of it as more or a “if anything is in this string/variable”.

However if there is a possibility that there might be empty space in the string (i.e., it’s " " instead of “”) then this will fail, because although a space looks empty, it’s still a character and thus the string is not empty. To cover those situations, you can also perform a check like this:

if (-not $string -or $string -match "^\s+$") {}

That will give the $true response if the string is either null, empty, or contains nothing but spaces.

Great… Thanks guys… You all are genius… Thanks a lot…

JS correction and Joel’s explanations help me to understand. Hats off to you guys…
Finally did this, and it worked…

$tar1=(Select-String -Pattern accounts -Path C:\type.txt).line if (-not $tar1) {
$tar1= 'Err.. Service Account Issue, Unable to perform Target Connectivity Test'

} else {

$tar1=(Select-String -Pattern accounts, performing, "done test list operation" -Path C:\type.txt).line.trim()

}