Hash#dig vs Hash#fetch

dig_vs_fetch.rb

require "benchmark"

h = { a: { b: { c: { d: { e: "foo" } } } } }

n = 50_000

Benchmark.bmbm(7) do |x|
  x.report "Hash#dig" do
    n.times do ; h.dig(:a, :b, :c, :d, :e); end
  end

  x.report "Hash#[]" do
    n.times do ; h[:a][:b][:c][:d][:e]; end
  end

  x.report "Hash#[] ||" do
    n.times do ; ((((h[:a] || {})[:b] || {})[:c] || {})[:d] || {})[:e]; end
  end

  x.report "Hash#[] &&" do
    n.times do ; h[:a] && h[:a][:b] && h[:a][:b][:c] && h[:a][:b][:c][:d] && h[:a][:b][:c][:d][:e]; end
  end

  x.report "Hash#fetch" do
    n.times do ; h.fetch(:a).fetch(:b).fetch(:c).fetch(:d).fetch(:e); end
  end

  x.report "Hash#fetch fallback" do
    n.times do ; h.fetch(:a, {}).fetch(:b, {}).fetch(:c, {}).fetch(:d, {}).fetch(:e, nil); end
  end
end

# Ruby 2.5.1 Results:
# 
# Rehearsal -------------------------------------------------------
# Hash#dig              0.008549   0.000020   0.008569 (  0.008586)
# Hash#[]               0.007598   0.000032   0.007630 (  0.007665)
# Hash#[] ||            0.008968   0.000049   0.009017 (  0.010046)
# Hash#[] &&            0.021017   0.000816   0.021833 (  0.023432)
# Hash#fetch            0.012320   0.001342   0.013662 (  0.013821)
# Hash#fetch fallback   0.020859   0.000659   0.021518 (  0.022696)
# ---------------------------------------------- total: 0.082229sec
# 
#                           user     system      total        real
# Hash#dig              0.008722   0.000156   0.008878 (  0.009031)
# Hash#[]               0.007424   0.000011   0.007435 (  0.007443)
# Hash#[] ||            0.008770   0.000074   0.008844 (  0.009877)
# Hash#[] &&            0.020502   0.000845   0.021347 (  0.022503)
# Hash#fetch            0.011854   0.000044   0.011898 (  0.012864)
# Hash#fetch fallback   0.018482   0.000767   0.019249 (  0.020280)