如何从年和周数中确定月份?

how to determine month from year and week number?

我想从周数和年数中获取月份名称:

date

Week    Year  
  52    2018
  20    2017
  47    2016

我们可以paste Week day , week number 和 year 一起转换成 Date 然后用 format 得到月份名称。阅读 ?strptime 格式选项

format(as.Date(paste(1, df$Week, df$Year), "%u %U %Y"), "%B")
#[1] "December" "May"      "November"

数据

df <- structure(list(Week = c(52L, 20L, 47L), Year = 2018:2016), 
     class = "data.frame", row.names = c(NA, -3L))