Avoid Select-Object output on screen

I am having a bit of trouble with Select-Object.

With the following piece of (truncated) code:

$totalData=(Get-Content $Env:TEMP\FBIUtemp2.txt)
.....
$data=""
....
....
$data =($totalData | Select-Object -Index ($s..$limit))
$data.Replace("`r`n"," ")
$data.Replace("`n"," ") 

I get a String (list of String separated with newline termination) from a file and get lines between $s and $limit into another $data String.

The code work as expected except that Select-Object keeps showing result on the screen and I would like for it not to do that.
I tried multiple things, but it either ends up doing nothing or stopping the script. I tried to mute the result with Out-Null, but then it doesn't fill the $data variable. Is there a parameter that I am missing?

Also, I don't want to split the $totalData String in a list to reassemble it later, as it would slow down the whole process.

Thank you for your help.

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It isn't Select-Object that produces visible output, it is your $data.Replace("`r`n"," ") and $data.Replace("`n"," ") method calls, both of which output the result of the string replacement - rather than modifying the input string(s) in place (something that is fundamentally unsupported, given that .NET strings are immutable).

$data contains an array of lines, whose elements by definition do not have embedded newlines (whether in the form of `n (LF) or `r`n (CRLF)).

If your intent is to join those lines with spaces:

$data = $data -join ' '