Sorting a file containing dates

subu_s · 06-03-2004, 06:45 AM

Hi,
I have a file which has data in the following format:-
15-dec-1992
11-nov-1992
26-apr-1993
15-mar-1993
19-jan-1993
05-oct-1990
21-jul-1992
03-dec-1991
15-feb-1991
22-jul-1993

I want to sort the dates in the reverse chronological order.

Please help providing a sample script or command.

Regards,
Subramanian S

ranger_nemo · 06-03-2004, 09:42 AM

Here's a quicky in Python...

Code:

months = { "jan":"A", "feb":"B", "mar":"C", "apr":"D", "may":"E", "jun":"F", "jul":"G", "aug":"H", "sep":"I", "oct":"J", "nov":"K", "dec":"L" }

temp = []
for entry in input:
  if entry <> "":
    splits = entry.split("-")
    outry = [splits[2] + months[splits[1]] + splits[0] , entry]
    temp.append(outry)

temp.sort()
temp.reverse()

output = []
for entry in temp:
  output.append(entry[1])

print output

I'll leave it up to you to work it into a real script with "input = infile.readlines()" and "outfile.writelines(output)" parts. It relys heavily on the input being formatted the same... double-digit day hyphen lower-case three-letter month hyphen four-digit year

phaserx · 06-03-2004, 01:07 PM

You could even just do something as simple as (where "dates" is the name of the file containing all the dates you want to sort):

awk -F- '{print $3"-"$2"-"$1}' dates | sort -r | awk -F- '{print $3"-"$2"-"$1}'

That will take this exact format:

15-dec-1992
11-nov-1992
26-apr-1993
15-mar-1993
19-jan-1993
05-oct-1990
21-jul-1992
03-dec-1991
15-feb-1991
22-jul-1993

And output it to look like this:

15-mar-1993
22-jul-1993
19-jan-1993
26-apr-1993
11-nov-1992
21-jul-1992
15-dec-1992
15-feb-1991
03-dec-1991
05-oct-1990