Range
lets( yr, prop("Date").year(), ifs( yr.test("1851|1900"), yr, yr >= 1800 && yr <= 1850, "1800–1850", yr >= 1901 && yr <= 1950, "1901–1950", yr >= 1951 && yr <= 2000, "1951–2000", yr >= 2001 && yr <= 2050, "2001–2050" ) )
Old Explanation
if(test(year(prop("Date")), "1851|1900"), format(year(prop("Date"))),If the year from Date exists in the pipe-separated list, simply display that year.
if(year(prop("Date")) >= #### and year(prop("Date")) <= ####, "####–####",Otherwise, for each range, check to see if the year from Date is greater than or equal to the first number and less than or equal to the second number. If so, display that range as a result.
