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Re: [PBML] Alphabetize a word

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  • Ryan J Nauman
    Ah, thanks. Neat little trick. Well I finished my first complete working version of the code and is a bit sluggish. Though this is expected since the input
    Message 1 of 15 , Sep 5, 2007
      Ah, thanks. Neat little trick. Well I finished my first complete working
      version of the code and is a bit sluggish. Though this is expected since
      the input file contains about 170,000 words stuffed into my @WORDS array.
      Wondering if you guys know any tricks to speed things up anywhere? Here
      is a link to my source code: http://pastie.textmate.org/94246

      Ryan




      Paul Archer <tigger@...>
      Sent by: perl-beginner@yahoogroups.com
      09/05/2007 11:28 AM
      Please respond to
      perl-beginner@yahoogroups.com


      To
      perl-beginner@yahoogroups.com
      cc

      Subject
      Re: [PBML] Alphabetize a word






      The slashes delimit a regular expression. In this case, the regexp is
      empty.
      Using an empty regular expression for the split means that each character
      will become a separate element in our array.

      Paul

      10:21am, Ryan J Nauman wrote:

      > What does the pattern " //" break down to? I'm somewhat familiar with
      > regular expressions and don't know what a forward slash does. I would
      > have guessed the matching pattern would've been the "." character that
      > matches any character (except \n).
      >
      >
      >
      >
      > Paul Archer <tigger@...>
      > Sent by: perl-beginner@yahoogroups.com
      > 09/05/2007 10:12 AM
      > Please respond to
      > perl-beginner@yahoogroups.com
      >
      >
      > To
      > perl-beginner@yahoogroups.com
      > cc
      >
      > Subject
      > Re: [PBML] Alphabetize a word
      >
      >
      >
      >
      >
      >
      > Which gets us to the oneliner:
      > perl -e ' $word="alphabetize"; print join "", (sort split ( //, $word)),
      > "\n"'
      >
      > 1:41pm, greenberg.d@... wrote:
      >
      >> As for returning it as a string instead of an array of characters, look
      > at the "join" function. With it, you can explicitly return a string.
      >>
      >> -David
      >>
      >> Sent via BlackBerry by AT&T
      >>
      >> -----Original Message-----
      >> From: Paul Archer <tigger@...>
      >>
      >> Date: Wed, 5 Sep 2007 08:20:52
      >> To:perl-beginner@yahoogroups.com
      >> Subject: Re: [PBML] Alphabetize a word
      >>
      >>
      >> If what you are looking for is a list of the letters in a word, in
      >> alphabetical order, then you want something like:
      >>
      >> perl -e ' $word="alphabetize"; @array= sort split ( //, $word); print
      >> @array, "\n"'
      >>
      >> And you're doing fine with the 'shift'. No reason not to do it just the
      > way
      >> you have it.
      >>
      >> Paul
      >>
      >> 9:13am, Ryan J Nauman wrote:
      >>
      >>> I wrote the following code to alphabetize a word:
      >>>
      >>> sub alphabetize
      >>> {
      >>> my $word = uc(shift);
      >>> my $wordlen = length($word);
      >>> my @letters;
      >>>
      >>> for (my $i = 0; $i < length $word; $i++)
      >>> {
      >>> push @letters, substr($word, $i, 1);
      >>> }
      >>>
      >>> @letters = sort @letters;
      >>> return @letters;
      >>> }
      >>>
      >>> This function will always only receive one parameter. In this case I
      > do
      >>> not know if shift is the best method or not. $_ was not giving me
      >>> anything so I went with shift. Alternatively, I think I could've used
      > @_.
      >>> Does it matter?
      >>>
      >>> If it can be optimized in any way I would appreciate pointers. My
      >>> ultimate question though is I want it to return a string instead of
      > the
      >>> sorted character array that it is now. I can write it using a for loop
      >>> and string concatenation but I think that would be extremely
      > inefficient.
      >>> Help appreciated!
      >>>
      >>>
      >>> [Non-text portions of this message have been removed]
      >>>
      >>>
      >>
      >> ---------------------------
      >> 404 Error - Item Not Found
      >> <haiku>
      >> You step in the stream,
      >> but the water has moved on.
      >> That page is not here.
      >> </haiku>
      >> ---------------------------
      >>
      >> -----11004 days until retirement!-----
      >>
      >>
      >> Unsubscribing info is here:
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      >> Yahoo! Groups Links
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      >>
      >>
      >>
      >>
      >
      > __________________________________________________________
      > "Can't you recognize bullshit? Don't you think it would be a
      > useful item to add to your intellectual toolkits to be capable
      > of saying, when a ton of wet steaming bullshit lands on your
      > head, 'My goodness, this appears to be bullshit'?
      > _____________Neal Stephenson, "Cryptonomicon"__________________
      >
      > -----11004 days until retirement!-----
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >
      >

      ---------------------------------------------------------
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      with strange cats." - Colonial American proverb
      ---------------------------------------------------------

      -----11004 days until retirement!-----



      [Non-text portions of this message have been removed]
    • merlyn@stonehenge.com
      ... Ryan Ah, thanks. Neat little trick. Well I finished my first complete working Ryan version of the code and is a bit sluggish. Though this is expected
      Message 2 of 15 , Sep 5, 2007
        >>>>> "Ryan" == Ryan J Nauman <RJNauman@...> writes:

        Ryan> Ah, thanks. Neat little trick. Well I finished my first complete working
        Ryan> version of the code and is a bit sluggish. Though this is expected since
        Ryan> the input file contains about 170,000 words stuffed into my @WORDS array.
        Ryan> Wondering if you guys know any tricks to speed things up anywhere? Here
        Ryan> is a link to my source code: http://pastie.textmate.org/94246

        Ooof, yeah. You're doing an exponential matching O(n squared)
        instead of just stashing everything according to its anagram.

        You need to use a "bucket" approach. As you compute each anagram,
        dump the original word into a bucket keyed by anagram, using a hash
        of arrayrefs...

        my %buckets;
        for my $word (@words) {
        my $alphaword = alphabetize($word);
        push @{$bucket{$alphaword}}, $word;
        }

        Now it's simply a matter of dumping each bucket:

        for my $alphaword (sort keys %bucket) {
        my $aref = $bucket{$alphaword};
        print "@$aref\n";
        }

        That will be infinitely faster when you get above a few hundred words.

        --
        Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
        <merlyn@...> <URL:http://www.stonehenge.com/merlyn/>
        Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
        See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
      • Ryan J Nauman
        Ah, excellent. However, allow my noobness to kick in. Alright so you want me to create a hash that contains the entire list of words (values) associated with
        Message 3 of 15 , Sep 5, 2007
          Ah, excellent. However, allow my noobness to kick in. Alright so you
          want me to create a hash that contains the entire list of words (values)
          associated with their alphabetized version (keys)? Should I do this as
          soon as I read in the input file? And should I continue with the line of
          code "my @WORDS = <INFILE>;" and create the bucket directly after?

          Now for the "dumping each bucket" portion I don't follow. Assuming I am
          following correctly on the first part, you're sorting the hash we made in
          the first step correct? I don't understand the print line. And is this
          used solely for sorting our newly created hash and then using my
          conditions against this new word list?

          Once the "bucket" hash is created would it be beneficial to my programs
          memory/execution time to close the INFILE and is there a way to delete the
          original @WORDS array now that the improved hash is in place?

          Thanks,
          Ryan




          merlyn@...
          Sent by: perl-beginner@yahoogroups.com
          09/05/2007 12:36 PM
          Please respond to
          perl-beginner@yahoogroups.com


          To
          Ryan J Nauman <RJNauman@...>
          cc
          perl-beginner@yahoogroups.com
          Subject
          Re: [PBML] Alphabetize a word






          >>>>> "Ryan" == Ryan J Nauman <RJNauman@...> writes:

          Ryan> Ah, thanks. Neat little trick. Well I finished my first complete
          working
          Ryan> version of the code and is a bit sluggish. Though this is expected
          since
          Ryan> the input file contains about 170,000 words stuffed into my @WORDS
          array.
          Ryan> Wondering if you guys know any tricks to speed things up anywhere?
          Here
          Ryan> is a link to my source code: http://pastie.textmate.org/94246

          Ooof, yeah. You're doing an exponential matching O(n squared)
          instead of just stashing everything according to its anagram.

          You need to use a "bucket" approach. As you compute each anagram,
          dump the original word into a bucket keyed by anagram, using a hash
          of arrayrefs...

          my %buckets;
          for my $word (@words) {
          my $alphaword = alphabetize($word);
          push @{$bucket{$alphaword}}, $word;
          }

          Now it's simply a matter of dumping each bucket:

          for my $alphaword (sort keys %bucket) {
          my $aref = $bucket{$alphaword};
          print "@$aref\n";
          }

          That will be infinitely faster when you get above a few hundred words.

          --
          Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777
          0095
          <merlyn@...> <URL:http://www.stonehenge.com/merlyn/>
          Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
          See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl
          training!



          [Non-text portions of this message have been removed]
        • Ryan J Nauman
          Can someone please help me understand what is being explained here? I thought I understood it after looking at it a second time but the part that confuses me
          Message 4 of 15 , Sep 7, 2007
            Can someone please help me understand what is being explained here? I
            thought I understood it after looking at it a second time but the part
            that confuses me now is the declare of "my %buckets" but we never use it,
            we use a scalar called $bucket. So, now I am completely lost.

            If someone could break it down, it'd be much appreciated.

            ------------------------
            Ryan



            merlyn@... (Randal L. Schwartz)
            09/05/2007 12:36 PM

            To
            Ryan J Nauman <RJNauman@...>
            cc
            perl-beginner@yahoogroups.com
            Subject
            Re: [PBML] Alphabetize a word






            >>>>> "Ryan" == Ryan J Nauman <RJNauman@...> writes:

            Ryan> Ah, thanks. Neat little trick. Well I finished my first complete
            working
            Ryan> version of the code and is a bit sluggish. Though this is expected
            since
            Ryan> the input file contains about 170,000 words stuffed into my @WORDS
            array.
            Ryan> Wondering if you guys know any tricks to speed things up anywhere?
            Here
            Ryan> is a link to my source code: http://pastie.textmate.org/94246

            Ooof, yeah. You're doing an exponential matching O(n squared)
            instead of just stashing everything according to its anagram.

            You need to use a "bucket" approach. As you compute each anagram,
            dump the original word into a bucket keyed by anagram, using a hash
            of arrayrefs...

            my %buckets;
            for my $word (@words) {
            my $alphaword = alphabetize($word);
            push @{$bucket{$alphaword}}, $word;
            }

            Now it's simply a matter of dumping each bucket:

            for my $alphaword (sort keys %bucket) {
            my $aref = $bucket{$alphaword};
            print "@$aref\n";
            }

            That will be infinitely faster when you get above a few hundred words.

            --
            Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777
            0095
            <merlyn@...> <URL:http://www.stonehenge.com/merlyn/>
            Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
            See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl
            training!



            [Non-text portions of this message have been removed]
          • Ryan J Nauman
            I have the following code for pushing a new value onto my hash: my %buckets; push(@{ $buckets{ KEYNAME } }, new value ); my @keys = keys %buckets; my @values
            Message 5 of 15 , Sep 7, 2007
              I have the following code for pushing a new value onto my hash:

              my %buckets;
              push(@{ $buckets{"KEYNAME"} }, "new value");
              my @keys = keys %buckets;
              my @values = values %buckets;
              print %buckets;
              print "\n@keys[0] => @values[0]";

              This code yields the following output...

              KEYNAMEARRAY(0x15d702c)
              KEYNAME => ARRAY(0x15d702c)

              Why won't it print "new value" ???

              I'm running perl, v5.8.8 build 822 from ActiveState.

              [Non-text portions of this message have been removed]
            • bike2ride
              ... With use strict; use warnings; you get the hint that you are not using Perl properly. Scalar value @keys[0] better written as $keys[0] at t.pl line 10.
              Message 6 of 15 , Sep 7, 2007
                --- In perl-beginner@yahoogroups.com, Ryan J Nauman <RJNauman@...> wrote:
                >
                > I have the following code for pushing a new value onto my hash:
                >
                > my %buckets;
                > push(@{ $buckets{"KEYNAME"} }, "new value");
                > my @keys = keys %buckets;
                > my @values = values %buckets;
                > print %buckets;
                > print "\n@keys[0] => @values[0]";
                >
                > This code yields the following output...
                >
                > KEYNAMEARRAY(0x15d702c)
                > KEYNAME => ARRAY(0x15d702c)
                >
                > Why won't it print "new value" ???
                >
                > I'm running perl, v5.8.8 build 822 from ActiveState.
                >
                > [Non-text portions of this message have been removed]
                >

                With

                use strict;
                use warnings;

                you get the hint that you are not using Perl properly.

                Scalar value @keys[0] better written as $keys[0] at t.pl line 10.
                Scalar value @values[0] better written as $values[0] at t.pl line 10.


                my %bucket = (
                KEYNAME => 'new value',
                ANOTHER => 'another value',
                );

                foreach my $key (keys %bucket) {
                print "key = $key, value = $bucket{$key}\n";
                }

                for more information -> web search "perl hash howto"

                gl
              • a_z0_9_blah
                ... Because $values[0] is an array reference. Try: print n$keys[0] = $values[0][0] ; If you want a better explanation, see:
                Message 7 of 15 , Sep 7, 2007
                  --- In perl-beginner@yahoogroups.com, Ryan J Nauman <RJNauman@...>
                  wrote:
                  >
                  > I have the following code for pushing a new value onto my hash:
                  >
                  > my %buckets;
                  > push(@{ $buckets{"KEYNAME"} }, "new value");
                  > my @keys = keys %buckets;
                  > my @values = values %buckets;
                  > print %buckets;
                  > print "\n@keys[0] => @values[0]";
                  >
                  > This code yields the following output...
                  >
                  > KEYNAMEARRAY(0x15d702c)
                  > KEYNAME => ARRAY(0x15d702c)
                  >
                  > Why won't it print "new value" ???

                  Because $values[0] is an array reference.

                  Try:
                  print "\n$keys[0] => $values[0][0]";

                  If you want a better explanation, see:
                  http://perldoc.perl.org/perldsc.html

                  (which wiil also lead you to several other manual pages to
                  understand Perls datastructures)

                  Chris
                • Jenda Krynicky
                  - OK then. - Because then it s all backwards. - Why is that? - Please don t top-post! ... Declare the %bucket hash. It s not initialized to anything, but will
                  Message 8 of 15 , Sep 8, 2007
                    - OK then.
                    - Because then it's all backwards.
                    - Why is that?
                    - Please don't top-post!


                    Ryan J Nauman <RJNauman@...> wrote:
                    > Ah, excellent. However, allow my noobness to kick in. Alright so you
                    > want me to create a hash that contains the entire list of words (values)
                    > associated with their alphabetized version (keys)? Should I do this as
                    > soon as I read in the input file? And should I continue with the line of
                    > code "my @WORDS = <INFILE>;" and create the bucket directly after?
                    >
                    > Now for the "dumping each bucket" portion I don't follow. Assuming I am
                    > following correctly on the first part, you're sorting the hash we made in
                    > the first step correct? I don't understand the print line. And is this
                    > used solely for sorting our newly created hash and then using my
                    > conditions against this new word list?
                    >
                    > Once the "bucket" hash is created would it be beneficial to my programs
                    > memory/execution time to close the INFILE and is there a way to delete the
                    > original @WORDS array now that the improved hash is in place?
                    >
                    > Thanks,
                    > Ryan

                    OK. Let me try to dissect the merlyn's code for you:

                    > merlyn@... wrote:
                    > Ooof, yeah. You're doing an exponential matching O(n squared)
                    > instead of just stashing everything according to its anagram.
                    >
                    > You need to use a "bucket" approach. As you compute each anagram,
                    > dump the original word into a bucket keyed by anagram, using a hash
                    > of arrayrefs...
                    >
                    > my %bucket;

                    Declare the %bucket hash. It's not initialized to anything, but will
                    be used as a HashOfArrays.

                    > for my $word (@words) {
                    > my $alphaword = alphabetize($word);

                    Let's sort the letters in the word

                    > push @{$bucket{$alphaword}}, $word;

                    And now let's the word at the the end of the array referenced by the
                    value of the hash %bucket using the key $alphaword.

                    When storing the first word containing a set of letters the
                    $bucket{$alphaword} doesn't exist in the hash, but that doesn't
                    matter. Perl will create it for us and as we are aparently expecting
                    the value to be a reference to an array ( @$ref is the array pointed
                    to by the reference stored in $ref) Perl even creates a brand new
                    array for us and stores its reference in $bucket{$alphaword}.

                    > }

                    Once this loop completes all words in the @words array have been
                    processed and are stored in the HashOfArrays named %bucket. They keys
                    are the sorted sets of letters and the values of the hash are
                    references to arrays containing the words.

                    You may clear the @words array now.

                    If your @words was created by
                    my @WORDS = <INFILE>;

                    You might actually get rid of the array completely and save memory.
                    Just remove that statement and change the loop to

                    while (my $word = <INFILE>) {
                    chomp($word);
                    my $alphaword = alphabetize($word);
                    push @{$bucket{$alphaword}}, $word;
                    }


                    > Now it's simply a matter of dumping each bucket:
                    >
                    > for my $alphaword (sort keys %bucket) {
                    > my $aref = $bucket{$alphaword};
                    > print "@$aref\n";
                    > }

                    As I said, %bucket is a hash of arrayrefs so in the loop above we get
                    the list of keys (the sorted sets of letters)
                    keys %bucket
                    sort it alphabetically
                    sort keys %bucket
                    and then loop through the sorted list, get the reference contained in
                    the hash and print the values in the referenced array.

                    HTH, Jenda

                    ===== Jenda@... === http://Jenda.Krynicky.cz =====
                    When it comes to wine, women and song, wizards are allowed
                    to get drunk and croon as much as they like.
                    -- Terry Pratchett in Sourcery
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