date_range = (Date.parse('2019-01-05')..Date.parse('2019-03-01'))
date_range.uniq { |d| d.month }
# => [Sat, 05 Jan 2019, Fri, 01 Feb 2019]
date_range.uniq { |d| d.cweek }
# => [Sat, 05 Jan 2019, Mon, 07 Jan 2019, Mon, 14 Jan 2019, Mon, 21 Jan 2019, Mon, 28 Jan 2019, Mon, 04 Feb 2019, Mon, 11 Feb 2019, Mon, 18 Feb 2019, Mon, 25 Feb 2019]