查找特定日期属于哪个季节

Question

我有一个日期向量，对于每个条目，我想分配一个季节。例如，如果日期在21.12之间。和21.3。我会说那是winter。到目前为止，我已经尝试了以下代码，但是无论年份如何，都无法使其更通用。my.dates <- as.Date("2011-12-01", format = "%Y-%m-%d") + 0:60low.date <- as.Date("2011-12-15", format = "%Y-%m-%d")high.date <- as.Date("2012-01-15", format = "%Y-%m-%d")my.dates[my.dates <= high.date & my.dates >= low.date]  [1] "2011-12-15" "2011-12-16" "2011-12-17" "2011-12-18" "2011-12-19" "2011-12-20" "2011-12-21" "2011-12-22" "2011-12-23" "2011-12-24" "2011-12-25"[12] "2011-12-26" "2011-12-27" "2011-12-28" "2011-12-29" "2011-12-30" "2011-12-31" "2012-01-01" "2012-01-02" "2012-01-03" "2012-01-04" "2012-01-05"[23] "2012-01-06" "2012-01-07" "2012-01-08" "2012-01-09" "2012-01-10" "2012-01-11" "2012-01-12" "2012-01-13" "2012-01-14" "2012-01-15"我尝试格式化不带年份的日期，但是它不起作用。ld <- as.Date("12-15", format = "%m-%d")hd <- as.Date("01-15", format = "%m-%d")my.dates[my.dates <= hd & my.dates >= ld]