# [Tutor] time calc

Roel Schroeven rschroev_nospam_ml at fastmail.fm
Mon Jun 21 08:16:25 EDT 2004

```kevin parks wrote:

> What i want to do is append the duration to the end of this list by
> subtracting the start of the item from the start time of the next so
> that the first line would look like:
>
> 1    1    1    00:23    08:00
> 1    2    2    8:23      01:18
>
> etc.
>
> So the task is really two part : reading in a list of numbers and adding
> one more piece of data and (2) doing time (base 60) math. It is the time
> math part i simply can't get my head around. Anyone know if there is a
> module that does time math? or a method for doing this by hand?

I don't know if there is a module that makes this easier, but here is
how I would do it by hand.

You basically have times consisting of an hour part and a minute part. I
would convert this to minutes by multiplying the hours with 60 and
adding it to the minutes: m = 60*h + m

Then do your math on the minutes alone, and convert back to hours and
minutes when done:

h = m % 60
m = m / 60

--
"Codito ergo sum"
Roel Schroeven

```