Replacing last characters after last comma with a string - powershell

Question

I have a huge text file which look like this:
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,3
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,8
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,14
36,53,15596,0.58454577855,0.26119,2.24878677855,0.116147072052964,12
The desired output is this:
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-03
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-08
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-14
36,53,15596,0.58454577855,0.26119,2.24878677855,0.116147072052964,MI-12
I have tried other relevant posts here and on other communities but could not exactly get what I want.
UPDATE
This is the cross-question (I wanted both Unix/perl answers and batch/powershell solutions for this.) that has interesting answers.

Answer 1

Here's a PowerShell answer in case you like PS.
Get-Content C:\Path\To\File.csv |
Where{$_ -match '^(.*,)([^,]*)$'} |
ForEach { "{0}MI-{1}" -f $Matches[1], $Matches[2].Padleft(2,'0') } |
Set-Content C:\Path\To\NewFile.csv

Answer 2

The next code does what you want except for filling with zero the last token when is less than 10, hope it helps.
EDIT: I figured out a way to insert a leading zero when the last number is less than 10. A little bit ugly but does it. :)
#echo off
setlocal EnableDelayedExpansion
for /F "delims=, tokens=1-8" %%A in (f.txt) do (
set /a "t=%%H-10"
if "!t:~0,1!" equ "-" (set "n=0%%H") else (set "n=%%H")
echo(%%A,%%B,%%C,%%D,%%E,%%F,%%G,MI-!n!>>f.new.txt
)
move /Y f.new.txt f.txt >nul 2>&1
For file (f.txt in this case):
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,3
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,8
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,14
36,53,15596,0.58454577855,0.26119,2.24878677855,0.116147072052964,12
Produces the following result (also in f.txt): updated
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-03
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-08
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-14
36,53,15596,0.58454577855,0.26119,2.24878677855,0.116147072052964,MI-12

Answer 3

Here is a cmd batch file that relies on a nice hack to split off the last item of a comma-separated list, independent on how many commas occur in the string. The basic technique is shown in the following; note that this requires delayed expansion to be enabled:
set "x=This,is,the,original,list."
set "y=" & set "z=%x:,=" & set "y=!y!,!z!" & set "z=%" & set "y=!y:~1!"
echo ORIGINAL: %x%
echo LAST ITEM: %z%
echo REMAINDER: %y%
So here is the code of the script, holding the above method in a sub-routine called :GET_LAST_ITEM:
#echo off
setlocal EnableExtensions DisableDelayedExpansion
rem // Define constants here:
set "_FILE=%~1" & rem // (specify the CSV file by the first argument)
for /F "usebackq delims=" %%L in ("%_FILE%") do (
call :GET_LAST_ITEM LAST REST "%%L"
setlocal EnableDelayedExpansion
set "LAST=0!LAST!"
echo(!REST!,MI-!LAST:~-2!
endlocal
)
endlocal
exit /B
:GET_LAST_ITEM rtn_last rtn_without_last val_string
::This function splits off the last comma-separated item of a string.
::Note that exclamation marks must not occur within the given string.
::PARAMETERS:
:: rtn_last variable to receive the last item
:: rtn_without_last variable to receive the remaining string
:: val_string original string
setlocal EnableDelayedExpansion
set "STR=,%~3"
set "PRE=" & set "END=%STR:,=" & set "PRE=!PRE!,!END!" & set "END=%"
endlocal & set "%~1=%END%" & set "%~2=%PRE:~2%"
exit /B

Answer 4

This is the answer that #RomanPerekhrest provided at my cross-question (I was also seeking unix/perl solutions) here:
awk approach with sprintf function(to add leading zeros):
awk -F, -v OFS=',' '$8="MI-"sprintf("%02d",$8);' file
The output:
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-03
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-08
36,53,90478,0.58699759849,0.33616,4.83449759849,0.0695335954050315,MI-14
36,53,15596,0.58454577855,0.26119,2.24878677855,0.116147072052964,MI-12