gistfile1.rb

# Referring to http://blog.rubybestpractices.com/posts/gregory/011-tap-that-hash.html

# Ruby 1.9, no tap, single line
Hash[[:x, :y, :z].map { |l| [l, rand(100)]}]

# Ruby 1.9/1.8, no tap, inject, single line
[:x, :y, :z].inject({}) { |result, l| result[l] = rand(100); result}

# Ruby 1.9/1.8, no tap, each_with_object from ActiveSupport, single line
[:x, :y, :z].each_with_object({}) { |l, result| result[l] = rand(100) }

# Ruby 1.8, no tap, single line
Hash[*[[:x, :y, :z].map { |l| [l, rand(100)]}].flatten]

# Ruby 1.9/1.8, no tap, initialed variable, multiline
result = {}
[:x, :y, :z].map { |l| result[l] = rand(100)}
result

# Ruby 1.9 no tap, expanded Hash[], multiline
Hash[
  [:x, :y, :z].map { |l| [l, rand(100)]}
]

# Ruby 1.9 tap single line
{}.tap { |result| [:x, :y, :z].map { |l| result[l] = rand(100)} }

# Ruby 1.9 tap multiline
{}.tap do |result|
  [:x, :y, :z].map do |l|
    result[l] = rand(100)
  end
end

# Ruby 1.9/1.8, returning from ActiveSupport, multiline
returning({}) do |result|  
  [:x, :y, :z].each do |l|  
    result[l] = rand(100)  
  end  
end

gistfile2.py

# Python 3
{(x, random.randrange(100)) for x in ["x", "y", "z"]}