Select only the attributes you want from a hash.

slice a hash.rb

# Select only the attributes you want from a hash.
# this is crazy useful when getting web parameters for example.
# ---------------------------------------------------------------------
require 'active_support/core_ext'
bacon = { delicious: true, color: "red" }
bacon.slice(:color)
# => { color:"red" }
# it returns a new hash, you can slice unknown keys and it still works.
# there's a lot of great stuff in active_support (from the rails gem)
# it mostly stands by itself but it's big so you can require just 'active_support/core_ext'
# to be more precise.  if you want everything in active_support do require 'active_support/all'
# but your global namespace might be too crowded.