Benchmark is_num methods

bench.rb

# from http://stackoverflow.com/questions/13149146/ruby-rails-determine-if-variable-is-a-number
require 'benchmark'

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

def is_num_r(num_given)
  num_given =~ /\d+(\.\d+)?/
end

Benchmark.bmbm do |x|
  x.report("exception w/valid input") { 100_000.times { |i| is_num_e("#{i}") } }
  x.report("regexp w/valid input")    { 100_000.times { |i| is_num_r("#{i}") } }

  x.report("exception w/invalid input") { 100_000.times { |i| is_num_e("a#{i}") } }
  x.report("regexp w/invalid input")    { 100_000.times { |i| is_num_r("a#{i}") } }
end

output.txt

Rehearsal -------------------------------------------------------------
exception w/valid input     0.050000   0.000000   0.050000 (  0.054714)
regexp w/valid input        0.160000   0.000000   0.160000 (  0.158725)
exception w/invalid input   1.120000   0.050000   1.170000 (  1.170184)
regexp w/invalid input      0.170000   0.000000   0.170000 (  0.170790)
---------------------------------------------------- total: 1.550000sec

                                user     system      total        real
exception w/valid input     0.050000   0.000000   0.050000 (  0.052318)
regexp w/valid input        0.160000   0.000000   0.160000 (  0.154336)
exception w/invalid input   1.060000   0.050000   1.110000 (  1.105803)
regexp w/invalid input      0.170000   0.000000   0.170000 (  0.171973)