Module: Random::HashExtensions

Included in:
Hash
Defined in:
lib/standard/facets/random.rb

Overview

Random extensions for Hash class.

Instance Method Summary collapse

Instance Method Details

#rand_key ⇒ Object

Returns a random key.

{:one => 1, :two => 2, :three => 3}.rand_key  #~> :three


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# File 'lib/standard/facets/random.rb', line 193

def rand_key
  keys.at(Random.number(keys.size))
end

#rand_key! ⇒ Object

Delete a random key-value pair, returning the key.

a = {:one => 1, :two => 2, :three => 3}
a.rand_key!  #~> :two
a            #~> {:one => 1, :three => 3}


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# File 'lib/standard/facets/random.rb', line 203

def rand_key!
  k,v = rand_pair
  delete(k)
  return k
end

#rand_pair ⇒ Object

Returns a random key-value pair.

{:one => 1, :two => 2, :three => 3}.rand_pair  #~> [:one, 1]


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# File 'lib/standard/facets/random.rb', line 213

def rand_pair
  k = rand_key
  return k, fetch(k)
end

#rand_pair! ⇒ Object

Deletes a random key-value pair and returns that pair.

a = {:one => 1, :two => 2, :three => 3}
a.rand_pair!  #~> [:two, 2]
a             #~> {:one => 1, :three => 3}


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# File 'lib/standard/facets/random.rb', line 224

def rand_pair!
  k,v = rand_pair
  delete( k )
  return k,v
end

#rand_value ⇒ Object

Returns a random hash value.

{:one => 1, :two => 2, :three => 3}.rand_value  #~> 2
{:one => 1, :two => 2, :three => 3}.rand_value  #~> 1


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# File 'lib/standard/facets/random.rb', line 235

def rand_value
  fetch(rand_key)
end

#rand_value! ⇒ Object

Deletes a random key-value pair and returns the value.

a = {:one => 1, :two => 2, :three => 3}
a.rand_value!  #~> 2
a              #~> {:one => 1, :three => 3}


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# File 'lib/standard/facets/random.rb', line 245

def rand_value!
  k,v = rand_pair
  delete( k )
  return v
end

#shuffle ⇒ Object

Returns a copy of the hash with values arranged in new random order.

h = {:a=>1, :b=>2, :c=>3}
h.shuffle  #~> {:b=>2, :c=>1, :a>3}


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# File 'lib/standard/facets/random.rb', line 257

def shuffle
  ::Hash.zip( keys.sort_by{Random.number}, values.sort_by{Random.number} )
end

#shuffle! ⇒ Object

Destructive shuffle_hash. Arrange the values in a new random order.

h = {:a => 1, :b => 2, :c => 3}
h.shuffle!
h  #~> {:b=>2, :c=>1, :a=>3}


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# File 'lib/standard/facets/random.rb', line 268

def shuffle!
  self.replace(shuffle)
end