How do I create a hash in Ruby that compares strings, ignoring case?

hash, key, ruby

Solution

To prevent this change from completely breaking independent parts of your program (such as other ruby gems you are using), make a separate class for your insensitive hash.

class HashClod < Hash
  def [](key)
    super _insensitive(key)
  end

  def []=(key, value)
    super _insensitive(key), value
  end

  # Keeping it DRY.
  protected

  def _insensitive(key)
    key.respond_to?(:upcase) ? key.upcase : key
  end
end

you_insensitive = HashClod.new

you_insensitive['clod'] = 1
puts you_insensitive['cLoD']  # => 1

you_insensitive['CLod'] = 5
puts you_insensitive['clod']  # => 5

After overriding the assignment and retrieval functions, it's pretty much cake. Creating a full replacement for Hash would require being more meticulous about handling the aliases and other functions (for example, #has_key? and #store) needed for a complete implementation. The pattern above can easily be extended to all these related methods.

Problem

In Ruby, I want to store some stuff in a Hash, but I don't want it to be case-sensitive. So for example: ``` h = Hash.new h["HELLO"] = 7 puts h["hello"] ``` This should output 7, even though the case is different. Can I just override the equality method of the hash or something similar? Thanks.

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