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Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)?

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John Salerno wrote:

> ::sigh:: Well, I'm stuck again and it has to do with my get_factors
> function again, I think. Even with the slight optimization, it's
> taking forever on 20! (factorial, not excitement)  :) It's frustrating
> because I have the Python right, but I'm getting stuck on the math.
> 
> The problem:
> 
> "What is the smallest positive number that is evenly divisible by all
> of the numbers from 1 to 20?"
> 
> 
> 
> Here's the function (it's in the problem3.py file, hence the import
> below):
> 
> import math
> 
> def get_factors(number):
>     factors = []
> 
>     for n in range(2, int(math.sqrt(number))):
>         if number % n == 0:
>             factors.append(n)
>             factors.append(number // n)
> 
>     return factors
> 
> And here's my new script for the new exercise:
> 
> import math
> from problem3 import get_factors
> 
> max_num = 20
> n = math.factorial(max_num)
> factors = get_factors(n)
> div_all = []
> 
> for x in factors:
>     for y in range(2, max_num+1):
>         if x % y != 0:
>             break
>         elif y == max_num:
>             div_all.append(x)
> 
> print(min(div_all))
> 
> It could easily be that I'm simply approaching it all wrong. I just
> thought that maybe using the factorial of the highest number in the
> range (in this case, 20) would be an easy way of finding which numbers
> to test.

These are almost "trick questions" in a way, because of the math behind 
them.  If the question were "What is the tallest high-school student in 
Scranton, PA?" then searching a population for the property would be the 
only way to go.  BUT you can also build up the answer knowing the 
factorization of all the numbers up to 20.

	Mel.

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How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 12:48 -0700
  Re: How can I speed up a script that iterates over a large range (600 billion)? Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-21 14:02 -0600
  Re: How can I speed up a script that iterates over a large range (600 billion)? Irmen de Jong <irmen@-NOSPAM-xs4all.nl> - 2011-06-21 22:10 +0200
    sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Irmen de Jong <irmen@-NOSPAM-xs4all.nl> - 2011-06-21 22:22 +0200
      Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 14:09 -0700
        Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2011-06-21 23:39 +0200
        Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-21 15:41 -0600
          Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 14:48 -0700
        Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Vlastimil Brom <vlastimil.brom@gmail.com> - 2011-06-21 23:33 +0200
        Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Paul Rubin <no.email@nospam.invalid> - 2011-06-21 17:05 -0700
          Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 18:21 -0700
            Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Paul Rubin <no.email@nospam.invalid> - 2011-06-21 19:09 -0700
              Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 20:02 -0700
                Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Irmen de Jong <irmen.NOSPAM@xs4all.nl> - 2011-06-22 19:46 +0200
            Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? MRAB <python@mrabarnett.plus.com> - 2011-06-22 03:10 +0100
            Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? Mel <mwilson@the-wire.com> - 2011-06-21 23:02 -0400
              Re: sorry, possibly too much info. was: Re: How can I speed up a script that iterates over a large range (600 billion)? John Salerno <johnjsal@gmail.com> - 2011-06-21 20:41 -0700
  Re: How can I speed up a script that iterates over a large range (600 billion)? Mel <mwilson@the-wire.com> - 2011-06-21 16:19 -0400
    Re: How can I speed up a script that iterates over a large range (600 billion)? Tim Roberts <timr@probo.com> - 2011-06-22 23:21 -0700
  Re: How can I speed up a script that iterates over a large range (600 billion)? MRAB <python@mrabarnett.plus.com> - 2011-06-21 21:26 +0100
  Re: How can I speed up a script that iterates over a large range (600 billion)? Terry Reedy <tjreedy@udel.edu> - 2011-06-21 19:30 -0400
    Re: How can I speed up a script that iterates over a large range (600 billion)? Paul Rubin <no.email@nospam.invalid> - 2011-06-21 17:00 -0700
      Re: How can I speed up a script that iterates over a large range (600 billion)? Terry Reedy <tjreedy@udel.edu> - 2011-06-22 00:18 -0400
        Re: How can I speed up a script that iterates over a large range (600 billion)? Paul Rubin <no.email@nospam.invalid> - 2011-06-21 22:32 -0700
          Re: How can I speed up a script that iterates over a large range (600 billion)? Terry Reedy <tjreedy@udel.edu> - 2011-06-22 18:46 -0400
  Re: How can I speed up a script that iterates over a large range (600 billion)? Benjamin Kaplan <benjamin.kaplan@case.edu> - 2011-06-21 20:07 -0700
  Re: How can I speed up a script that iterates over a large range (600 billion)? Chris Torek <nospam@torek.net> - 2011-06-22 05:58 +0000
    Re: How can I speed up a script that iterates over a large range (600 billion)? Paul Rubin <no.email@nospam.invalid> - 2011-06-21 23:23 -0700
      Re: How can I speed up a script that iterates over a large range (600 billion)? Slaunger <slaunger@gmail.com> - 2011-06-23 02:52 -0700
    Re: How can I speed up a script that iterates over a large range (600 billion)? Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-22 01:16 -0600
    Re: How can I speed up a script that iterates over a large range (600 billion)? Anny Mous <b1540457@tyldd.com> - 2011-06-22 22:01 +1000
      Re: How can I speed up a script that iterates over a large range (600 billion)? Chris Angelico <rosuav@gmail.com> - 2011-06-22 22:28 +1000
      Re: How can I speed up a script that iterates over a large range (600 billion)? Ian Kelly <ian.g.kelly@gmail.com> - 2011-06-22 09:52 -0600
    Re: How can I speed up a script that iterates over a large range (600 billion)? MRAB <python@mrabarnett.plus.com> - 2011-06-22 16:33 +0100

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