15 Exercises to Know A Programming Language

John Machin sjmachin at lexicon.net
Tue Jul 3 13:47:10 CEST 2007

On Jul 3, 7:58 pm, Martin <martin.clau... at gmail.com> wrote:
> I am trying to improve my Python skills through some exercises.
> Currently I am working on Larry's "15 exercises to know a programming
> language " (http://www.knowing.net/
> PermaLink,guid,f3b9ba36-848e-43f8-9caa-232ec216192d.aspx). The first
> exercise is this:
> "Write a program that takes as its first argument one of the words
> 'sum,' 'product,' 'mean,' or 'sqrt'  and for further arguments a
> series of numbers. The program applies the appropriate function to
> the series."
> My solution so far is this:
> http://dpaste.com/13469/
> I would really like some feedback. Is this a good solution? is it
> efficient? robust? what could be improved? any not looking for a
> revised solution, hints on what to improve are also very welcome.
> Martin

sum is a builtin function in Python 2.3 and later. You could do
something like this:

except NameError:
    def sum(args):
        return reduce(operator.add, args)

Tested with 2.5 back to 2.1, and 1.5.2 :-)

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