31 lines
891 B
Ruby
31 lines
891 B
Ruby
require 'set'
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module ActiveSupport #:nodoc:
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module CoreExtensions #:nodoc:
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module Hash #:nodoc:
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# Slice a hash to include only the given keys. This is useful for
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# limiting an options hash to valid keys before passing to a method:
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#
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# def search(criteria = {})
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# assert_valid_keys(:mass, :velocity, :time)
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# end
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#
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# search(options.slice(:mass, :velocity, :time))
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module Slice
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# Returns a new hash with only the given keys.
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def slice(*keys)
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allowed = Set.new(respond_to?(:convert_key) ? keys.map { |key| convert_key(key) } : keys)
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hash = {}
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allowed.each { |k| hash[k] = self[k] if has_key?(k) }
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hash
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end
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# Replaces the hash with only the given keys.
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def slice!(*keys)
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replace(slice(*keys))
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end
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end
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end
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end
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end
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