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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]# Program to find Primes of the form prime(n+2) * prime(n+1) - prime(n) +- 1.

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On Thu, 04 Oct 2018 09:44:01 +0100, Tony van der Hoff wrote: > On 04/10/18 09:31, Alister via Python-list wrote: >> On Wed, 03 Oct 2018 09:43:07 -0700, Musatov wrote: >> >>> On Wednesday, October 3, 2018 at 11:12:43 AM UTC-5, Michael Torrie >>> wrote: >>>> On 10/03/2018 09:26 AM, Musatov wrote: >>>>> I don't even know where to begin! (I'm reading the Dummies book) >>>> >>>> If you have no experience in computer programming, it's going to be a >>>> steep learning curve. >>>> >>>> But your first step is to learn Python and how to write programs in >>>> it. >>>> That book and others will help with that. You'll have to write lots >>>> of simple programs unrelated to primes along the way that help you >>>> understand programming concepts. >>>> >>>> If you already have experience in other languages, the task will be >>>> easier. >>>> >>>> Computer programming is quite natural to some (small children seem to >>>> get it much easier than us adults), but I've seen others struggle to >>>> grasp the abstract concepts for years. >>>> >>>> Once you've grasped basic Python programming, you can return top the >>>> original problem at hand. Start by identifying the process or >>>> algorithm that would find these primes. In other words, how would you >>>> do it on pen and paper? Computer programs are not magic. They are >>>> only expressions of human thinking. Often some very smart >>>> mathematicians have come up with powerful algorithms (a step-by-step >>>> process) to do these things, >>>> and your job as a programmer is to turn this mathematical process >>>> into a computer program using things like loops and Boolean logic. >>>> How would you find these primes using your pen, paper, and >>>> calculator? >>> >>> Literally, how I found them was taking a list of primes and checking >>> if the calculations with the lesser primes resulted in numbers also >>> further along on the list. >>> >>> Another way I guess would be to do the calculations then check if the >>> number is prime. >> >> That is exactly how you do it with in a program. >> >> create a loop & check to see if the target number can be divided by >> each possible divisor in turn . >> for large numbers this will take a large number of tests (hey that is >> why you have the computer do them, it is faster than you & does not get >> bored ;-) ) there are numerous tricks for speeding up this process once >> you have the basic working. >> >> start by testing small numbers & then use your real data once you have >> something that works >> >> as a starter a simple loop in python could be as follows >> >> for x in xrange(10): >> print x >> >> once you have an outline of a program post it back here if things dont >> work as expected >> >> > Two lines, two errors! To save the noob a lot of head-scratching, that > should be: > for x in range(10): > > If you're running python 3, as you should do for any new project: > print( x ) perfectly legit python 2.7 I probably should have considered writing python 3 compatible code but range operates differently on the 2 versions & would be a poor choice for python 2 when numbers get larger ass for the head scratching a noob (& anyone else for that mater) far more from correcting code than they do from simply copy & pasting working code. -- TAILFINS!! ... click ...

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