pronoun
which; which ones
Emphatic or reduplicated form of どれ. As a pronoun, it is much less common than どれ or どれとどれ in ordinary modern speech.
See also: どれ
必要な品はどれどれですか。
Which items are needed?
interjection
Interjection used to prompt, encourage, or urge someone to do something; often has a kindly or coaxing tone.
どれどれ、もう一度やってごらん。
Come on, try it once more.
どれどれ、話してみなさい。
Well now, tell me about it.