rubocop app controller function validate param integer use of nil? predicate

Question

I tried rewriting this function numerous ways to get around this error, however, I want to defer to other experts before I disable the cop around it.

  def numeric?(obj)
    obj.to_s.match(/\A[+-]?\d+?(\.\d+)?\Z/) == nil ? false : true
  end

This is used like so:

  def index
    if params[:job_id] && numeric?(params[:job_id])

Update trying:

  def numeric?(string)
    !!Kernel.Float(string)
  rescue TypeError, ArgumentError
    false
  end

New error:

score 1 · Answer 1 · answered Feb 19 '16 at 07:43

1

The following code snippet does the trick:

def numeric?(arg)
  return false if arg.is_a?(Float)
  return !Integer(arg).nil? rescue false
end

Returns false for the following: 'a', 12.34, and '12.34'.

Returns true for the following: '1', 1.

answered Feb 19 '16 at 07:43

Eli Foster

score 1 · Accepted Answer · answered Feb 19 '16 at 19:16

1

def numeric?(arg)
  !/\A[+-]?\d+\z/.match(arg.to_s).nil?
end

Passes all Rubocop tests from a default configuration. Complete gist with tests at https://gist.github.com/aarontc/d549ee4a82d21d263c9b

answered Feb 19 '16 at 19:16

aarontc

score 0 · Answer 3 · answered Feb 19 '16 at 04:58

0

You can write the method

def numeric?(obj)
  obj.to_s.match(/\A[+-]?\d+?(\.\d+)?\Z/).nil?
end

You really don't need to do nil comparisons and then based on the decision returning true/false. #nil? method does it for you.

answered Feb 19 '16 at 04:58

Arup Rakshit

when integer params are passed i.e. "8" it returned false – Chris Hough Feb 19 '16 at 05:27
Ok, that is because of your regex. The answer was to address the rubocop error. To check the object is a Integer or not, you may try http://ruby-doc.org/core-2.3.0/Kernel.html#method-i-Integer – Arup Rakshit Feb 19 '16 at 05:28
well, the other answer does both, is there a way to incorporate both? I would prefer to use regex in this case, it seems much easier – Chris Hough Feb 19 '16 at 05:31
Why not try already attempted code ? http://stackoverflow.com/questions/5661466/test-if-string-is-a-number-in-ruby-on-rails :D http://stackoverflow.com/questions/26061584/how-do-i-determine-if-a-string-is-numeric – Arup Rakshit Feb 19 '16 at 05:33
the other one allows decimals... http://stackoverflow.com/questions/5661466/test-if-string-is-a-number-in-ruby-on-rails – Chris Hough Feb 19 '16 at 05:46
@chrishough I use double `!!` a lot. I don't know why it is a bad idea though. – Arup Rakshit Feb 19 '16 at 05:48
1

I ignored the cop after this chat, seems appropriate – Chris Hough Feb 19 '16 at 06:05

3 Answers3