PowerShell - how to check "Not Contains" clause?-CodePudding

I want to check if PATH in windows server contains some string. If it doesn't I wish to add it to the PATH. I want to add this "CommonLib" folder. I try to do it immediately in IF clause:

  > $CommonLib="C:\Program Files\Front\CommonLib"
  > if (($env:Path -split ";").NotContains($CommonLib)) {Write-Host "executing the code"}
    InvalidOperation: Method invocation failed because [System.String] does not contain a method named 'NotContains'.

Contains is recognized (I can do it probably by executing the code in ELSE clause) but NotContains isn't. How can I resolve this? Thanks!!!

CodePudding user response：

The else branch is a solid option. It's simple to write and understand. Like so,

if (($env:Path -split ";").Contains($CommonLib)) {
  Write-Host "$CommonLib is in path"
} else {
  Write-Host "$CommonLib is NOT in path"
}

It's also possible to do the test and store the result in a variable. Logic operators like -not can be used to invert its value. It's usually much more clear to test if something is something than someting is not someting. Like so,

$CLInPath = ($env:Path -split ";").Contains($CommonLib)
if(-not $CLInPath) {
  Write-Host "$CommonLib is NOT in path"    
}

This avoids if..else branching, which is desired if the other branch doesn't do anything.

CodePudding user response：

You can use the not operator with the Contains function.

if (!($env:Path -split ";").Contains($CommonLib)) {Write-Host "executing the code"}

CodePudding user response：

The other answers here provide viable alternatives to your issue and arguably better approaches, but to answer your specific question, you need to use the -NotContains operator as so:

if (($env:Path -split ";") -NotContains $CommonLib) {
    Write-Host "executing the code"
}