function to convert degree (hour), minute, seconds string to integer

[John Machin]

google0 at lazytwinacres.net wrote:
> John Machin wrote:
> > google0 at lazytwinacres.net wrote:
> > > I know this is a trivial function, and I've now spent more time
> > > searching for a surely-already-reinvented wheel than it would take to
> > > reinvent it again, but just in case... is there a published,
> > > open-source, function out there that takes a string in the form of
> > > "hh:mm:ss" (where hh is 00-23, mm is 00-59, and ss is 00-59) and
> > > converts it to an integer (ss + 60 * (mm + 60 * hh))?  I'd like
> > > something that throws an exception if hh, mm, or ss is out of range, or
> > > perhaps does something "reasonable" (like convert "01:99" to 159).
> > > Thanks,
> > >     --dang
> >
> > Have you considered time.strptime()?
> >
> > BTW, your function, given "00:00:00" will return 0 -- you may well have
> > trouble distinguishing that from False (note that False == 0), without
> > resorting to ugliness like:
> >
> >     if result is False ...
> >
> > Instead of returning False for some errors and letting int() raise an
> > exception for others, I would suggest raising ValueError yourself for
> > *all* invalid input.
> >
> > You may wish to put more restrictions on the separators ... I would be
> > suspicious of cases where dms[2] != dms[5]. What plausible separators
> > are there besides ":"? Why allow alphabetics? If there's a use case for
> > "23h59m59s", that would have to be handled separately. Note that
> > "06-12-31" could be a date, "12,34,56" could be CSV data.
> >
> > Cheers,
> > John
>
> Good point about 0/False.  I don't think it would have bitten me in my
> current program, given my expected (and filtered) inputs, but I might
> have reused it in the future, and been bitten later.

The bigger pain would have been two types of error handling
(try/except) *AND* if result is False
>
> I had looked at the time module, but apparently not long enough.
> This does the trick:
>
> def dms2int(dms):
>     int(time.mktime(time.strptime("2000-01-01 %s" % dms, "%Y-%m-%d
> %H:%M:%S")))
>
> I only need the minutes, but can work with seconds.  The only downside
> is that I'm hardcoding an arbitrary date, but I can deal with that.
>

That's a bit too elaborate. Python gives you the hard-coded date for
free -- then (you ingrate!) you ignore it, like this:

|>> import time
|>> dms = "23:48:59"
|>> t = time.strptime(dms, "%H:%M:%S")
|>> t
(1900, 1, 1, 23, 48, 59, 0, 1, -1)
|>> seconds = (t[3] * 60 + t[4]) * 60.0 + t[5]
|>> seconds
85739.0 # assuming you do want it as a float, not an int

Cheers,
John