Any good idea on how to traverse with Datetime objects?

[Bjorn Madsen]

Hi Campug,

Does anyone out there have a good pythonic idea on how to traverse through datetime (python 3.2.3)?

>>> startDate # 2000-1-1

datetime.datetime(2000, 1, 1, 0, 0)

>>> endDate # 2000-12-31

datetime.datetime(2000, 12, 31, 0, 0)

>>> timestep # every 2 hours

datetime.timedelta(0, 7200)

>>> 

Unfortunately the following solution doesn't work as intended:

dictionary={}

for i in range(startDate, endDate, timestep):      # <<<< TypeError: 'datetime.datetime' object cannot be interpreted as an integer

    dictionary[i]=someValue

Kind Regards,

--

Bjorn 

[Stephen Paulger]

I'm not sure you'd call it pythonic but it works at least.

>>> from datetime import datetime, timedelta

>>> start = datetime(2000, 1, 1)

>>> end = datetime(2000, 1, 2)

>>> current = start

>>> while current < end:

...     print current

...     current += timedelta(hours=2)

...

2000-01-01 00:00:00

2000-01-01 02:00:00

2000-01-01 04:00:00

2000-01-01 06:00:00

2000-01-01 08:00:00

2000-01-01 10:00:00

2000-01-01 12:00:00

2000-01-01 14:00:00

2000-01-01 16:00:00

2000-01-01 18:00:00

2000-01-01 20:00:00

2000-01-01 22:00:00

--
You received this message because you are subscribed to the Google Groups "Cambridge and East Anglian Python Users Group" group.
To post to this group, send email to cam...@googlegroups.com.
To unsubscribe from this group, send email to campug+un...@googlegroups.com.
For more options, visit this group at http://groups.google.com/group/campug?hl=en.

[Bjorn Madsen]

Looks neat enough to me. Thanks Stephen.

Kind Regards, 

Bjorn

[David Reynolds]

You might want to look at python-dateutil http://labix.org/python-dateutil/


--
David Reynolds
da...@reynoldsfamily.org.uk

> --
> You received this message because you are subscribed to the Google Groups "Cambridge and East Anglian Python Users Group" group.

> To post to this group, send email to cam...@googlegroups.com (mailto:cam...@googlegroups.com).
> To unsubscribe from this group, send email to campug+un...@googlegroups.com (mailto:campug+un...@googlegroups.com).

[Stephen Paulger]

Maybe it's slightly more python to do it as a generator.

>>> def date_range(start, end, step):

...     while start < end:

...             yield start

...             start += step

...

>>> from datetime import datetime, timedelta

>>> date_range(datetime(2000, 1, 1), datetime(2000, 1, 2), timedelta(hours=2))

<generator object date_range at 0xb734d4dc>

I suppose you could replace the condition with "while end is None or start < end:" that way you could pass None as the second argument to make it generate forever.

Steve

On 23 July 2012 15:50, Stephen Paulger <stephen...@newspeak.org.uk> wrote:

[Dougal Matthews]

Why not make a datetime aware range? Something like this; http://dpaste.com/774212/

(Just typed that directly into the browser, it probably wont work)

Dougal

On Monday, 23 July 2012 at 15:16, Bjorn Madsen wrote:

> --
> You received this message because you are subscribed to the Google Groups "Cambridge and East Anglian Python Users Group" group.

> To post to this group, send email to cam...@googlegroups.com (mailto:cam...@googlegroups.com).
> To unsubscribe from this group, send email to campug+un...@googlegroups.com (mailto:campug+un...@googlegroups.com).

[Bjorn Madsen]

Hi Dougal,

That was clever! Splendid idea!

Thanks.

Bjorn

def daterange(start, end, step):

    current = start
    while current < end:

        current += step
        yield current

startdate = datetime(2000, 1, 1, 0, 0)
enddate = datetime(2000, 12, 31, 0, 0)
timestep = timedelta(0, 7200)


for i in daterange(startdate, enddate, timestep):
    pass

To post to this group, send email to cam...@googlegroups.com.
To unsubscribe from this group, send email to campug+un...@googlegroups.com.

For more options, visit this group at http://groups.google.com/group/campug?hl=en.

--

Bjorn Madsen

Researcher Complex Systems Research

Ph.: (+44) 0 7792 030 720 

bjorn....@operationsresearchgroup.com

[Didrik Pinte]

Depending on what you want to do, you should consider the datetime
support of numpy:

http://docs.scipy.org/doc/numpy/reference/arrays.datetime.html (look for arange)

-- Didrik

On 23 July 2012 22:12, Bjorn Madsen

Didrik Pinte +32 475 665 668
+44 1223 969515
Enthought Europe dpi...@enthought.com
Scientific Computing Solutions http://www.enthought.com