Question

如何设置长度为84的变量，为非闰年的前84天提供正确的月份（使用标签“jan”，“feb”，“march”）？

Answer 1

您可以执行以下操作（更改year的值以选择其他年份）：

year <- 2001
days <- as.Date(paste(year, "/01/01", sep = "")) + seq.int(0, 83)
months(days, abbreviate = TRUE)
# [1] "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan"
#[13] "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan"
#[25] "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Jan" "Feb" "Feb" "Feb" "Feb" "Feb"
#[37] "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb"
#[49] "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Feb" "Mar"
#[61] "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar"
#[73] "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar" "Mar"

您可以按如下方式检查年份是否为闰年：

if (table(months(days))["February"] == 29)
  cat(paste(year, "is a leap year.\n"))

Answer 2

Altenative＃1：

library(zoo)
days <- as.Date('2014-01-01') + seq.int(84)-1
get_month_given_date <- zoo(months(days, abbreviate = TRUE),order.by=days)
#Example
get_month_given_date[as.Date('2014-02-28')]
get_month_given_date[as.Date(c('2014-01-03','2014-03-04'))]

备选方案＃2：

library(zoo)
strsplit(as.character(as.yearmon("2007-03-01"))," ")[[1]][1]

闰年检查：

is_leap_year <- function(year){if((year%%4==0 & year%%100!=0) | year%%400==0 ) return(TRUE) else return(FALSE)}
#Examples
is_leap_year(2000)
is_leap_year(1900)
is_leap_year(2012)
is_leap_year(2014)

在非闰年的前84天编写R代码

2 个答案: