·

956

· slawosz

Not everyone knows, that Hash class constructor in ruby can be used to initialize default value of hash.

For example, if our hash values will be arrays, instead of:

h = {}
h[:foo] = []
h[:foo] << :bar

We can initialize hash in this way:

h = Hash.new { |key, value| key[value] = [] }
h[:foo] << :bar

That is much more ruby :)

And how you would return how many times each word is in some document (ie. array?):

I would write such code:

class Inc

 attr_reader :value

 def initialize
 @value = 0
 end

 def inc
 @value += 1
 end

 def inspect
 value
 end
end

h = Hash.new { |k,v| k[v] = Inc.new }

%(some array of words).each { |word| h[word].inc }

And now h stores words as keys and words counts in array as values.

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