benchmark.rb

#!/usr/bin/ruby
require 'benchmark'
include Benchmark

pi = 3.14
n = 1000000

Benchmark.benchmark(" "*7 + CAPTION, 7, FMTSTR) do |x|
  to_i = x.report("to_i:")   { n.times { pi != pi.to_i } }
  gsub = x.report("gsub:")   { n.times { pi.to_s.gsub(/^.*\.(.*)$/, '\1').to_i > 0 } }
  mod  = x.report("mod:")    { n.times { pi % 1 != 0 } }
  fc   = x.report("fc:")     { n.times { pi.floor != pi.ceil } }
end

benchmark_results

             user     system      total        real
to_i:    0.410000   0.000000   0.410000 (  0.410188)
gsub:    6.050000   0.020000   6.070000 (  6.093139)
mod:     0.530000   0.000000   0.530000 (  0.529583)
fc:      0.490000   0.000000   0.490000 (  0.494660)