Sort Date Field String

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  • andrew
    #1

    Sort Date Field String

    Hi:

    I am already using TreeMap to massage records in my export file such that
    each record has a unique key combination ( LastName + FirstName + Member
    Key) . Thus I am sorting the records by the unique key. I also have a Date
    String Field in my record ( ie "30-Apr-2005" ). I want to create a unique
    key combination of
    ( LastName + FirstName + Member Key + Date).

    Can you please tell me what are the steps I need to do to sort the Date
    String Field? Obviously, I can't treat the date as a string field because
    it will sort the date alphabetically ( ie 30-Apr-2005 will come before
    30-Jan-2005 ).




    Thanks in advance

    Andrew


    Tags: None
    • Thomas Dybdahl Ahle
      #2
      Re: Sort Date Field String

      Den Tue, 04 Oct 2005 09:12:58 -0400. skrev andrew:[color=blue]
      > I am already using TreeMap to massage records in my export file such that
      > each record has a unique key combination ( LastName + FirstName + Member
      > Key) . Thus I am sorting the records by the unique key. I also have a Date
      > String Field in my record ( ie "30-Apr-2005" ). I want to create a unique
      > key combination of
      > ( LastName + FirstName + Member Key + Date).[/color]

      What about making/using a method for turning dates into an int or long.
      Then making a SortedMap using the number as key and string as value.

      It's all about making/using a fast algorithm for the convertion.

      --
      Programmers should realize their critical importance and responsibility in a
      world gone digital. They are in many ways similar to the priests and monks of
      Europe's Dark Ages; they are the only ones with the training and insight
      to read and interpret the "scripture" of this age.

        Comment

        • andrew
          #3
          Re: Sort Date Field String

          Thanks for the reply. I found a solution by using Date, and
          SimpleDateForma t class to do the sorting of the date fields:

          String strDateFormat = "dd-MMM-yyyy";
          SimpleDateForma t dfDate = new SimpleDateForma t(strDateFormat );
          Date dateKey = null;
          dateKey = dfDate.parse( datefield ); // datefield has the
          string value "31-Jan-2005" etc.


          Then I can put dateKey as part of the key in a TreeMap so that it can be
          sorted. :)

          Thank you.


          "Thomas Dybdahl Ahle" <thomas@localho st.localdomain> wrote in message
          news:pan.2005.1 0.04.16.14.53.7 00495@localhost .localdomain...[color=blue]
          > Den Tue, 04 Oct 2005 09:12:58 -0400. skrev andrew:[color=green]
          > > I am already using TreeMap to massage records in my export file such[/color][/color]
          that[color=blue][color=green]
          > > each record has a unique key combination ( LastName + FirstName + Member
          > > Key) . Thus I am sorting the records by the unique key. I also have a[/color][/color]
          Date[color=blue][color=green]
          > > String Field in my record ( ie "30-Apr-2005" ). I want to create a[/color][/color]
          unique[color=blue][color=green]
          > > key combination of
          > > ( LastName + FirstName + Member Key + Date).[/color]
          >
          > What about making/using a method for turning dates into an int or long.
          > Then making a SortedMap using the number as key and string as value.
          >
          > It's all about making/using a fast algorithm for the convertion.
          >
          > --
          > Programmers should realize their critical importance and responsibility in[/color]
          a[color=blue]
          > world gone digital. They are in many ways similar to the priests and monks[/color]
          of[color=blue]
          > Europe's Dark Ages; they are the only ones with the training and insight
          > to read and interpret the "scripture" of this age.
          >[/color]


            Comment

            • David Moss
              #4
              Re: Sort Date Field String

              In article <Obv0f.1899$R4. 253037@news20.b ellglobal.com>, andrew@abc.com
              writes...
              [color=blue]
              > Hi:
              >
              > I am already using TreeMap to massage records in my export file such that
              > each record has a unique key combination ( LastName + FirstName + Member
              > Key) . Thus I am sorting the records by the unique key. I also have a Date
              > String Field in my record ( ie "30-Apr-2005" ). I want to create a unique
              > key combination of
              > ( LastName + FirstName + Member Key + Date).
              >
              > Can you please tell me what are the steps I need to do to sort the Date
              > String Field? Obviously, I can't treat the date as a string field because
              > it will sort the date alphabetically ( ie 30-Apr-2005 will come before
              > 30-Jan-2005 ).[/color]

              Date objects store the date as the number of milliseconds since a
              particular point in time.

              Instead of storing your dates in human readable form as a String, store
              the number instead. That way you can sort and compare very quickly.

              You can also reconstruct a Date object from the number any time you like
              and use standard Java date manipulation and comparison techniques with
              it.

              --
              DM
              personal opinion only

                Comment

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