String Interpolation using Hash Vs. String Interpolation. Benchmark on ruby 1.9.3 to verify which one has a better performance.

benchmark-string-result

       user     system      total        real
hash interpolation  0.300000   0.010000   0.310000 (  0.301211)
string interpolation  0.090000   0.000000   0.090000 (  0.098942)

       user     system      total        real
hash interpolation  0.290000   0.010000   0.300000 (  0.301891)
string interpolation  0.140000   0.000000   0.140000 (  0.135461)

       user     system      total        real
hash interpolation  0.310000   0.010000   0.320000 (  0.318774)
string interpolation  0.100000   0.000000   0.100000 (  0.109029)

       user     system      total        real
hash interpolation  0.300000   0.010000   0.310000 (  0.303394)
string interpolation  0.100000   0.000000   0.100000 (  0.099212)

string-interpolation-benchmark

require 'benchmark'

module Visit
  PLANNED = 'planned'
  DATE = '2016-02-13'
end

n = 100000
Benchmark.bm do |x|
   x.report('hash interpolation') do
     n.times do
       s = "visit.status = %{visit_status} AND visit.planned_date < %{visit_planned_date}" % { visit_status: Visit::PLANNED, visit_planned_date: Visit::DATE }
     end
   end
   x.report('string interpolation') do
      n.times do
        s = "visits.status = '#{Visit::PLANNED}' and visits.planned_date < '#{Visit::DATE}'"
      end
   end
end