Differences between literals and constructors? ([] vs Array.new and {} vs Hash.new)

Question

I was curious to know more differences between [] and Array.new and {} and Hash.new

I ran same benchmarks on it and seems like the shorthands are winners

Answer 1

Robert already mentioned the default value of the Hash.new

You may also use compley 'default'-values with the block variant of Hash.new:

x = Hash.new { |hash, key|
  hash[key] = key * 2
}

p x      #-> {}
p x[1]   #-> 2
p x      #-> {1=>2}

Array.new can also be used to get default values:

p Array.new(5, :a)  #-> [:a, :a, :a, :a, :a]