How to split a string variable in powershell and rename a folder - powershell

Question

does anybody know how to split a string variable in Powershell and rename the file by adding a number and file extension?
My scenario and example of variables I'm using:
$return_path = "C:\FolderA\result.txt"
How do I get the "C:\FolderA\result" portion? I have tried Split-Path but I keep getting this error below. Even though there is indeed a value in $return_path but it still says that it is null
Error splitting File Path
Also I am trying to loop through a dataset and I need to append "i" to the retrieved file name after I split it, for example, "C:\FolderA\result[i].txt", but currently, my code below is outputting an error which is attached at Screenshot 3 below. Is the error because I cannot check if an integer is less than number of data set returned? Any answers would be appreciated as I need help after trying and researching but I am still stuck. Thank you.
Looping through retrieved tables from dataset (Count how many tables returned)
Error comparing in loop

Answer 1

For your ask, Try this :
$return_path = "C:\FolderA\result.txt"
#get file name extension
$FileExtension=[System.IO.Path]::GetExtension($return_path)
#get file name without extension
$FileNameWithoutExtension=[System.IO.Path]::GetFileNameWithoutExtension($return_path)
#get directory path
$Directory=[System.IO.Path]::GetDirectoryName($return_path)
for ($i = 1; $i -lt $ds.Tables.Count; $i++)
{
#build file name
$PathFile=[System.IO.Path]::Combine($Directory, $FileNameWithoutExtension + $i + $FileExtension)
#export current table
$ds.Tables[$i] | export-csv $PathFile -Delimiter '|' -notypeinformation
}
But ideally your should do it :
$initdir = "C:\FolderA\" # define your inital directory
$FileName="result" # define your final file name
$Extension=".CSV" #use csv and not txt extension for csv file
for ($i = 1; $i -lt $ds.Tables.Count; $i++)
{
#build file name
$PathFile=[System.IO.Path]::Combine($initdir, $FileName + $i + $Extension)
#export current table
$ds.Tables[$i] | export-csv $PathFile -Delimiter '|' -notypeinformation
}