[Tutor] Need help with dates in Python

[nookasree ponamala]

Thanks for your help Francesco. This works.

Sree.

--- On Fri, 3/11/11, Francesco Loffredo <fal at libero.it> wrote:

> From: Francesco Loffredo <fal at libero.it>
> Subject: Re: [Tutor] Need help with dates in Python
> To: tutor at python.org
> Date: Friday, March 11, 2011, 1:05 AM
> On 09/03/2011 9.21, nookasree
> ponamala wrote:
> > Hi,
> >
> > I need help in finding the minimum date and maximum
> date in a file.
> > Here is my test file:
> > s.no:    dt1   
> amt    id1    id2
> > 452     2010-02-20   
>   $23.26      059542     
>   06107
> > 452     2010-02-05   
>   $20.78      059542     
>   06107
> > 451     2010-02-24   
>   $5.99       059542 
>       20151
> > 452     2010-02-12   
>   $114.25     839745   
>     98101
> > 452     2010-02-06   
>   $28.00      839745     
>   06032
> > 451     2010-02-12   
>   $57.00      839745     
>   06269
> >
> > I want to get the minimum and maximum dt1 for each
> id1
> >
> > Required result:
> >
> > id1 mindate maxdate
> > 059542    2010-02-24   
> 2010-02-20        
> > 839745    2010-02-06   
> 2010-02-12
> >
> > Code: The code I tried. It doesn't work though.
> 
> I noticed that your dates are formatted in a way that makes
> it easy to compare them as strings.
> This allows you not only to do without splitting dates into
> year, month and day, but also to do without the datetime
> module:
> I'm also, AFAIK, the first one to address your need for the
> min and max date FOR EACH ID1, not in the whole file.
> 
> .    ids = {}  # create an empty dictionary
> to store results
> .    for L in open("test.txt", "r"):
> .      S = L.split()  # allow direct
> access to fields
> .      if S[3] in ids:
> .        mindate, maxdate =
> ids[S[3]]  # current stored minimum and maximum date
> .        if S[1] < mindate:
> .          mindate = S[1]
> .        if S[1] > maxdate:
> .          maxdate = S[1]
> .        ids[S[3]] = (mindate,
> maxdate)  # new stored min and max
> .      else:
> .        ids[S[3]] = (S[1], S[1]) 
> # initialize storage for the current id1, with min and max
> in a tuple
> .    #leave print formatting as an exercise to
> the reader (but you can do without it!)
> .    print ids
> 
> Hope this helps...
> Francesco
> 
> 
> -----
> Nessun virus nel messaggio.
> Controllato da AVG - www.avg.com
> Versione: 10.0.1204 / Database dei virus: 1497/3495 - 
> Data di rilascio: 09/03/2011
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> http://mail.python.org/mailman/listinfo/tutor
>