Question

Possible Duplicate:
Test if string is a number in Ruby on Rails

Currently I have this (awful) code:

def is_num(num_given)
  begin
    num_given.to_i
    worked = true
  rescue
    worked = false
  ensure
    return worked
  end
end

Which I refactored to this:

def is_num(num_given)
  num_given.to_i.is_a?(Numeric) rescue false
end

This still just doesn’t feel right to me, is there a better way to do this?

Both of these implementations work fine for my purposes, I am just looking for some code euphoria.

Answer 1

The functions you listed won’t work:

is_num("a") #=> true

The problem is that they don’t raise an error for invalid input. What you want is Integer, which will raise an error which you can rescue:

def is_num(num_given)
  !!Integer(num_given) rescue false
end

This works:

irb(main):025:0> is_num("a")
=> false
irb(main):026:0> is_num(5)
=> true
irb(main):027:0> is_num((1..2))
=> false
irb(main):028:0> is_num("3")
=> true

(There may be a more natural way to do this, though.)