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Re: Understanding Python Code

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On Thursday, June 19, 2014 12:45:49 AM UTC+5:30, Ian wrote:
> 
> 
> > The questions are,
> 
> > i) prev_f_sum = sum(f_prev[k]*a[k][st] for k in states)
> 
> > here f_prev is called,
> 
> > f_prev is assigned to  f_curr ["f_prev = f_curr"]
> 
> > f_curr[st]  is again being calculated as, ["f_curr[st] = e[st][x_i] * prev_f_sum"] which again calls "prev_f_sum"
> 
> >
> 
> > I am slightly confused which one would be first calculated and how to proceed next?
> 
> 
> 
> These things that you describe as "calls" are not calls.  f_prev and
> 
> f_curr are data structures (in this case dicts), not functions.
> 
> Accessing "f_prev[k]" does not call f_prev or in any way cause
> 
> f_prev[k] to be computed; it just looks up what value is recorded in
> 
> the f_prev dict for the key k.
> 
> 
> 
> Python is an imperative language, not declarative.  If you want to
> 
> know what order these things are calculated in, just follow the
> 
> program flow.

Thank you for the reply. But as I checked it again I found,
f_prev[k] is giving values of f_curr[st] = e[st][x_i] * prev_f_sum
which is calculated later and again uses prev_f_sum.

Regards,
Subhabrata Banerjee. 

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Understanding Python Code subhabangalore@gmail.com - 2014-06-18 09:36 -0700
  Re: Understanding Python Code Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-18 13:15 -0600
    Re: Understanding Python Code subhabangalore@gmail.com - 2014-06-18 22:50 -0700
      Re: Understanding Python Code Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-19 01:00 -0600
        Re: Understanding Python Code subhabangalore@gmail.com - 2014-06-19 02:48 -0700
          Re: Understanding Python Code Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-19 08:09 -0600
            Re: Understanding Python Code subhabangalore@gmail.com - 2014-06-19 07:27 -0700
              Re: Understanding Python Code subhabangalore@gmail.com - 2014-06-19 11:44 -0700
                Re: Understanding Python Code Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-19 13:07 -0600
                Understanding Python Code[Forward_Backward_Wikipedia] subhabangalore@gmail.com - 2014-06-21 15:05 -0700

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