[ruby-talk:11794] Re: building n-grams

Arno Erpenbeck <[e-mail]> writes:

> Example:
> Input "The man sees the boy with the telescope."
> Output "The, ma,n s,ees, th,e b,oy ,wit,h t,he ,tel,esc,ope,"
> Desired output "The,he ,e m, ma,man,..."


One solutoin is simply to index slices out of the string. Here's an
example wrapped as an iterator, but that's kind of incidental.


     def ngram(str, n)
         pos = 0
         while pos <= str.length - n
           yield str[pos, n]
           pos += 1
         end
     end

     ngram("The man sees the boy with the telescope.", 3) {|txt| puts txt}

produces:

     The
     he 
     e m
      ma
     man
     ...
     cop
     ope
     pe.


Regards


Dave