How to correctly execute a command along with an element from an array in Powershell?

Question

PowerShell

There is an array in which Python modules are stored, it is required to execute the command pip install+ module from the array for each element.
It gives the following error:

& : The name "pip install urllib" is not recognized as the name of a cmdlet, function, script file, or executable. Check
the spelling of the name and the presence and correctness of the path, then repeat

experience.
$modules = "urllib", "pandas", "selenium", "requests", "numpy"
for($i=0; $i -lt $modules.length; $i++) {
& "pip install $($modules [$i])"
}

Answer 1

try moving the quote:
& "pip install $($modules[$i])"
like this:
& "pip" install $($modules[$i])
ps without quotes, this line also works fine. I really only on cats, ugh, I tried ping -n 1....

Answer 2

Maybe so:

$modules.ForEach( {
        Start-Process -FilePath "<path_to_pip>pip.exe" -ArgumentList "install $_" -PassThru -Wait
    }
)