Using 'if' for a string variable in powershell

Question

Hi All,

I'm just trying to understand the usage of the 'if' in a specific context.

From my understanding when you run an If statement, PowerShell evaluates the <test1> conditional expression as true or false.

However, in the below piece of code, we're seeing the 'if' operator is used on a variable that contains a lot of data content (which has been a result of a command retrieving certain info)

$LatestLog = Get-EventLog -LogName System -After (Get-Date).AddDays(-5)

if($LatestGPLog) #if machine processed GPO within 7 days
{
return $true
}

In the absence of a conditional expression in the above statement, is the 'if' statement just checking for presence or absence of content within the variable and proceeding further? Or am I missing something?

Thanks in advance.

• SV

Answer 1

Hi @SAMUEL VALAPARLA ,

the if($LatestGPLog) is true if the variable $LatestGPLog contains "something", which means $LatestGPLog is "not Null" or "is not empty".
Instead of if($LatestGPLog) you can use if($LatestGPLog -ne $null)

The opposite of if($LatestGPLog) - "variable is not Null" is if(!$LatestGPLog) - variable is "!empty or null"
Or if($LatestGPLog -eq $null)

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten

Answer 2

Regardless of the two earlier answers, they aren't completely true.

Given the "if the variable contains something" statement, what do you think the result of this little bit of code will be? The variable $x contains an integer, and that qualifies as "something", no?

$x = 0  
if ($x){$true} else {$false}  
$null -eq $x  

Answer 3

just checking for presence or absence of content within the variable

Right, as a vers simple example:

$var  
if ($var) { Write-Host "Has value" } else { Write-Host "Has no value" }  
$var = 1234  
if ($var) { Write-Host "Has value" } else { Write-Host "Has no value" }