计算r中的月天数

library(dplyr)

df %>%
  # distinct(date) %>% # unnecessary if no dupe dates
  mutate(month = lubridate::floor_date(date, "month")) %>%
  count(month)

后果

       month n
1 2005-12-01 2
2 2006-01-01 3
3 2006-02-01 1
4 2007-03-01 3
5 2007-04-01 2

使用的数据:

df <- structure(list(date = structure(c(13145, 13148, 13149, 13150, 
13151, 13183, 13574, 13575, 13578, 13613, 13614), class = "Date")), row.names = c(NA, 
-11L), class = "data.frame")

df %>% mutate(date = format(.$date, "%Y-%m")) %>% group_by(date) %>% count(date) -> out

out以tibble的形式按年份和月份为您提供摘要。

这是另一个解决方案,

a <- as.Date(c("2005-12-28", "2005-12-31", "2006-01-01",
  "2006-01-02", "2006-01-03", "2006-02-04",
  "2007-03-02", "2007-03-03", "2007-03-06",
  "2007-04-10", "2007-04-11"))

date <- strsplit(as.character(a) , "-")
# to extract months
months <- lapply(date , function(x) x[2])
# to extract years
years <- lapply(date , function(x) x[1])

table(unlist(months))
#> 
#> 01 02 03 04 12 
#>  3  1  3  2  2

table(unlist(years))
#> 
#> 2005 2006 2007 
#>    2    4    5

^{创建日期:2022-06-01 reprex package (v2.0.1)}