ruby-struct-init.rb

require 'benchmark'

LOOP = 500000
NKEYS = 20

vals = (0..NKEYS).map {|i| "val#{i}" }
keys = (0..NKEYS).map {|i| "col#{i}" }

S = Struct.new(*keys.map {|k| k.to_sym })

Benchmark.bmbm do |x|
  x.report("Struct#[]=") {
    LOOP.times do
      obj = S.new
      (0..NKEYS).each {|i| obj[keys[i]] = vals[i] }
    end
  }

  x.report("Struct.new") {
    LOOP.times do
      S.new *(0..NKEYS).map {|i| vals[i] }
    end
  }

  x.report("Struct.new + codegen") {
    code = eval("proc {|vals| S.new(#{(0..NKEYS).map {|i| "vals[#{i}]" }.join(',')}) }")
    LOOP.times do
      code.call(vals)
    end
  }

  x.report("Hash#[]=") {
    LOOP.times do
      obj = {}
      (0..NKEYS).each {|i| obj[keys[i]] = vals[i] }
    end
  }

  x.report("Hash.new(zip)") {
    LOOP.times do
      vals_array = (0..NKEYS).map {|i| vals[i] }
      Hash[keys.zip(vals_array)]
    end
  }

  x.report("Hash.new + codegen") {
    kv_code = (0..NKEYS).map {|i| "#{keys[i].dump},vals[#{i}]" }
    code = eval("proc {|vals| Hash[#{kv_code.join(',')}] }")
    LOOP.times do
      code.call(vals)
    end
  }
end

__END__
Rehearsal --------------------------------------------------------
Struct#[]=             2.740000   0.000000   2.740000 (  2.748829)
Struct.new             1.540000   0.000000   1.540000 (  1.549932)
Struct.new + codegen   0.390000   0.010000   0.400000 (  0.387977)
Hash#[]=               4.350000   0.000000   4.350000 (  4.360114)
Hash.new(zip)          5.820000   0.010000   5.830000 (  5.829954)
Hash.new + codegen     4.100000   0.000000   4.100000 (  4.118849)
---------------------------------------------- total: 18.960000sec

                           user     system      total        real
Struct#[]=             2.760000   0.010000   2.770000 (  2.766344)
Struct.new             1.590000   0.000000   1.590000 (  1.612082)
Struct.new + codegen   0.370000   0.000000   0.370000 (  0.374896)
Hash#[]=               4.400000   0.010000   4.410000 (  4.415043)
Hash.new(zip)          5.890000   0.010000   5.900000 (  5.904067)
Hash.new + codegen     4.110000   0.000000   4.110000 (  4.138564)

ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0]
Darwin xcore 13.2.0 Darwin Kernel Version 13.2.0: Thu Apr 17 23:03:13 PDT 2014; root:xnu-2422.100.13~1/RELEASE_X86_64 x86_64 i386 MacBookPro10,1 Darwin