Re: Hash Function

[Sergei Steshenko]

----- Original Message -----
> From: Jordi Gutiérrez Hermoso <address@hidden>
> To: Jonathan Karsch <address@hidden>
> Cc: address@hidden
> Sent: Wednesday, December 5, 2012 5:35 PM
> Subject: Re: Hash Function
> 
> On 5 December 2012 10:07, Jonathan Karsch <address@hidden> wrote:
>>  I am trying to figure out how many distinct words are in a text
>>  document, and how many instances there are of each.
> 
> Octave does not have hashes nor sufficiently flexible associative
> arrays. I recommend using a language other than Octave for this task.
> For example, here is how you can do it in Python:
> 
>     #!/usr/bin/env python
> 
>     import sys
>     from collections import defaultdict
> 
>     f = open(sys.argv[1])
> 
>     wordcount = defaultdict(int)
> 
>     for line in f.readlines():
>         words = line.split()
>         for word in words:
>             wordcount[word] += 1
> 
>     f.close()
> 
>     for word, count in wordcount.iteritems():
>         print "%s: %d" % (word, count)
> 
> 
> Here is how to do it in Perl:
> 
>     #!/usr/bin/env perl -w
> 
>     use strict;
> 
>     my %wordcount;
>     while(<>){
>       my @words = split;
>       foreach my $word (@words){
>         $wordcount{$word}++;
>       }
>     }
> 
> 
>     while (my ($word, $count) = each %wordcount){
>       print "$word: $count\n";
>     }
> 
> 
> Both languages are installed already in your McIntosh PC. Put either
> of those programs into a file named count_words, give it executable
> permissions, and do "./count_words somefile".
> 
> HTH,
> - Jordi G. H.
> _______________________________________________
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> https://mailman.cae.wisc.edu/listinfo/help-octave


Jordi,

why are you posting distracting info ?


It _is_ possible to do this in Octave (with all my love for Perl, and you know 
it.


Here is a _simple_ demo:

"
octave:1> system("cat -n /home/sergei/junk/hash_demo.m");
     1  words_to_count = {"John", "Paul", "Mary", "Julia", "John", "Paul", 
"John"};
     2
     3  hash = struct;
     4
     5  for word_number = 1:numel(words_to_count)
     6    if(isfield(hash, words_to_count{word_number}))
     7      hash = setfield(hash, words_to_count{word_number}, getfield(hash, 
words_to_count{word_number}) + 1);
     8    else
     9      hash = setfield(hash, words_to_count{word_number}, 1);
    10    endif
    11  endfor
    12
    13
    14  hash
octave:2> source("/home/sergei/junk/hash_demo.m");
hash =

  scalar structure containing the fields:

    John =  3
    Paul =  2
    Mary =  1
    Julia =  1

octave:3>     
".

Regards,
  Sergei.


>