How do I confirm all elements in a hash are defined?

What is the best way to check if all the objects in the Ruby hash are defined (not nil)?

The statement should return false if at开发者_JAVA技巧 least one element in the hash is nil.

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You can use all? to check whether a given predicate is true for all elements in an enumerable. So:

hash.values.all? {|x| !x.nil?}

Or

hash.all? {|k,v| !v.nil?}

If you also want to check, all the keys are non-nil as well, you can amend that to:

hash.all? {|k,v| !v.nil? && !k.nil?}

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Another way:

!hash.values.include? nil

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Enumerable#all? method does exactly what you need.

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An element (value) that is nil is defined. It's defined as the nil object.

If you're wanting to check if there's any keys missing, then do the following:

hash = {:key1 => nil, :key2 => 42, :key3 => false}
keys = [:key1, :key2, :key3]
all_defined = keys.all?{|key| hash.has_key?(key)} # Returns true

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hash = { foo: nil, bar: nil, baz: nil }
hash.values.all?(nil) # true
!hash.values.all?(nil) # false


hash = { foo: 0, bar: nil, baz: nil }
hash.values.all?(nil) # false
!hash.values.all?(nil) # true