gistfile1.rb

require 'benchmark'
include Benchmark
n = 1000000
Benchmark.bm do |test|

  test.report("Double quotes:") do
    n.times do |x|
      str = "A string with a \newline"
      str = "Interpolates #{12345}"
    end
  end
  
  test.report("Single quotes:") do
    n.times do |x|
      str = 'A string with a \newline'
      str = 'Interpolates #{12345}'
    end
  end
  
end

#       user     system      total        real
# Double quotes:  5.490000   2.120000   7.610000 (  7.652372)
# Single quotes:  4.220000   2.100000   6.320000 (  6.345824)