Converting time to seconds using arithmetic operators - batch-file

Question

I'm trying to convert a time value from a text file from hr:min:sec.sec to just seconds. I have a file with event numbers (consecutive order, 1,2,3 etc.) in column 1 of each row and the rest of the row is event data as in my example below. I want to have the user enter two numbers, with which my script grabs the corresponding hr:min:sec of each event and converts into only seconds.
The file format is 4 000-01:04:10.983745 34.56 string1 string_2 (this would be the 4th line, its date/time, a duration in seconds, and two static strings in the next two columns.
I am using a for loop to grab tokens 1, 2, and 3 using : as the delims and then just trimming the strings for the purpose of performing arithmetic.
So %%A should be 4 000-01, %%B should be 04, and %%C should be everything else on the line. Now I just read batch doesn't support decmials, so I can do without them if needed. But this isn't returning anything:
setlocal enabledelayedexpansion enableextension
REM auto-setting event values for testing
set begin=3
set end=4
for /f "tokens=1,2,3 delims=:" %%A in ('findstr /b /c:"!begin![^0-9]" event.txt') do (
set "hr=%%A"
set /A "min=%%B"
set "sec=%%C"
set /A "hr=!hr:~-2!"
set /A "sec=!sec:~0,2!"
set /A "total=(hr*3600)+(min*60)+sec"
echo !total!>>time.txt
)
exit /B

Answer 1

If your file format is:
line 4 000-01:04:10.983745 34.56 string1 string_2
delim - : : .
token 1 2 3 4
var - A B C
A common technic to avoid the leading zero/octal problem is to prefix
a two place decimal with a literal 1 and subtract 100.
Set /A allows multiple calculations on a line seperated by a comma, the vars don't need to be enclosed in percent signs (doesn't apply to for/arg vars).
#Echo off
setlocal enabledelayedexpansion enableextensions
for /f "tokens=2-4 delims=-:." %%A in (
'findstr /b /C:"4 " event.txt'
) do Set /A "hr=1%%A-100,min=1%%B-100,sec=1%%C-100,total=hr*3600+min*60+sec"
echo Total is %total% (hr=%hr%, min=%min%, sec=%sec%)
echo %total% >>time.txt
exit /B
Sample output:
Total is 3850 (hr=1, min=4,sec=10)

Answer 2

Here is an approach that regards the fractional seconds also, rounded to six fractional figures:
#echo off
setlocal EnableExtensions DisableDelayedExpansion
rem // Define constants here:
set "_SOURCE=event.txt"
set "_TARGET=time.txt"
set "_REGEX=^[0-9][0-9]* [0-3][0-9][0-9]-[0-9][0-9]:[0-5][0-9]:[0-5][0-9].[0-9][0-9]* "
rem // Convert filtered lines:
> "%_TARGET%" (
for /F "tokens=1-9* delims=:.- " %%A in ('findstr /R /C:"%_REGEX%" "%_SOURCE%"') do (
rem // Extract and store hour, minute, second values:
set "HOUR=1%%C" & set "MIN=1%%D" & set "SEC=1%%E"
rem // Extract and store fractional seconds and also the static strings:
set "FRAC=1%%F0000000" & set "STR1=%%I" & set "STR2=%%J"
rem // Convert hour, minute, second values to decimal integers:
set /A "HOUR%%=100, MIN%%=100, SEC%%=100"
setlocal EnableDelayedExpansion
rem // Convert fractional seconds to decimal number:
set /A "FRAC=!FRAC:~,7!%%1000000+!FRAC:~7,1!/5"
rem // Compute integer seconds, round to 6 decimal places:
set /A "SEC+=60*(MIN+60*HOUR)+FRAC/1000000" & set "FRAC=000000!FRAC!"
rem // Rebuilt line with time value replaced by fractional seconds:
echo %%A %%B-!SEC!.!FRAC:~-6! %%G.%%H !STR1! !STR2!
endlocal
)
)
endlocal
exit /B