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
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