Array of hashes to hash

Question

For example, I have array of single hashes

a = [{a: :b}, {c: :d}]

What is best way to convert it into this?

{a: :b, c: :d}
         


        

Answer 1

I came across this answer and I wanted to compare the two options in terms of performance to see which one is better:

1. a.reduce Hash.new, :merge
2. a.inject(:merge)

using the ruby benchmark module, it turns out that option (2) a.inject(:merge) is faster.

code used for comparison:

require 'benchmark'

input = [{b: "c"}, {e: "f"}, {h: "i"}, {k: "l"}]
n = 50_000

Benchmark.bm do |benchmark|
  benchmark.report("reduce") do
    n.times do
      input.reduce Hash.new, :merge
    end
  end

  benchmark.report("inject") do
    n.times do
      input.inject(:merge)
    end
  end
end

the results were

       user     system      total        real
reduce  0.125098   0.003690   0.128788 (  0.129617)
inject  0.078262   0.001439   0.079701 (  0.080383)