string_append_vs_plus_equals.rb

require 'benchmark'

n = 500_000
Benchmark.bm(7) do |x|
  x.report('append:') do
    a = ''
    n.times { a << 'a' }
  end

  x.report('+=:') do
    a = ''
    n.times { a += 'a' }
  end

  x.report('=+:') do
    a = ''
    n.times { a = a + 'a' }
  end
end

$ ruby -w string_append_vs_plus_equals.rb             [14:31:14]
              user     system      total        real
append:   0.100000   0.000000   0.100000 (  0.101719)
+=:      27.500000  14.360000  41.860000 ( 41.860157)
=+:      27.110000  14.020000  41.130000 ( 41.131695)