Hi, I recently took a coding challenge for a job, and as part of my application they sent me a coding challenge I had to pass.
Today I received the answer, and I've been rejected. No big deal, I already found a job I like a lot (and part of it will be in Erlang, yay!), but the comments they made over my code left me... baffled. I would like to have if possible a code review (
really not a lot of code) and some comments over the issues they point out.

The task was "Write a program that prints a multiplication table of primes numbers."
I will omit the one-liner Thor script that actually generates the thing, and post my implementation.

class Fixnum
def erathostenes
starting_array = (2..self).to_a
starting_array.each_with_index do |n, outer|
(outer..(starting_array.count - 1)).each do |inner|
if Fixnum.erathostenes_sieves?(starting_array[inner], starting_array[outer])
starting_array[inner] = nil
end
end
starting_array.compact!
end
end

def self.erathostenes_sieves?(number, dividend)
number % dividend == 0 && number / dividend != 1
end
end

Here is the class that prints the table:

module FundingCirclePrimeTable
class Table
attr_reader :numbers, :rows

def initialize(count)
@count = count
@numbers = @count.erathostenes
@rows = @numbers.collect {|n| [n] + @numbers.last(@count - 1).map {|i| (i * n).to_s }}
end

def to_s
Terminal::Table.new(headings: @numbers.map(&:to_s).unshift(' '), rows: @rows)
end
end
end

Yes, the attr_reader in the last class isn't needed, I added it for simplicity when writing tests, and at some point I used an each_with_index and forgot about the index, my bad, left some dirty when refactoring, my bad and I count it as a problem in my
code.
They told me that "The feedback from the team showed that the tests provided complete coverage, however the code had a few issue regarding naming and organising and contained quite a few clusters of functionality in a few lines."
Also consider I'm not a native english speaker.
What you guys think? Maybe it's because I opened Fixnum?...

TIA,
ngw

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On 18.05.2016 11:23, ngw@nofeed.org wrote:

They told me that "The feedback from the team showed that the tests
provided complete coverage, however the code had a few issue
regarding naming and organising and contained quite a few clusters of functionality in a few lines."

I find that way too unspecific to comment. What is this supposed to
mean? If they have something to complain about they should address
specific items - if only that you can learn from it.

Also consider I'm not a native english speaker.
What you guys think? Maybe it's because I opened Fixnum?...

That method should have gone into Integer if at all.

Kind regards

robert

--
remember.guy do |as, often| as.you_can - without end http://blog.rubybestpractices.com/

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ngw@nofeed.org wrote:

The task was "Write a program that prints a
multiplication table of primes numbers."

require 'prime'

def prime_mul_table n
a = Prime.take(n)
width = (a[-1]**2).to_s.size
matrix = [" ",*a].zip((a + a.product(a).map{|m,n| m*n}).each_slice(n)).
map{|x,xs| [x,*xs].map{|x| x.to_s.rjust(width)}.join " "}
end

prime_mul_table(12).each{|r| puts r}
2 3 5 7 11 13 17 19 23 29 31 37
2 4 6 10 14 22 26 34 38 46 58 62 74
3 6 9 15 21 33 39 51 57 69 87 93 111
5 10 15 25 35 55 65 85 95 115 145 155 185
7 14 21 35 49 77 91 119 133 161 203 217 259
11 22 33 55 77 121 143 187 209 253 319 341 407
13 26 39 65 91 143 169 221 247 299 377 403 481
17 34 51 85 119 187 221 289 323 391 493 527 629
19 38 57 95 133 209 247 323 361 437 551 589 703
23 46 69 115 161 253 299 391 437 529 667 713 851
29 58 87 145 203 319 377 493 551 667 841 899 1073
31 62 93 155 217 341 403 527 589 713 899 961 1147
37 74 111 185 259 407 481 629 703 851 1073 1147 1369


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