有没有简单的方法可以从 R 中的当前日期获取上个月的开始日期和结束日期？
我只有当前日期。从中，我想获取上个月，上个月的开始日期，上个月的结束日期。
currentDate<-Sys.Date() #return today's date as "2012-11-07"
我希望上个月的开始日期为 2012-10-01，结束日期为今天的 2012-10-31。
问问题
29848 次
7 回答
38
许多包都有方便的日期功能，但要自己动手：
月初功能：
som <- function(x) {
as.Date(format(x, "%Y-%m-01"))
}
和月末函数（虽然你在这里不需要这个）：
eom <- function(x) {
som(som(x) + 35) - 1
}
那应该让你继续前进。例如，要获得上个月的月底：
som(Sys.Date()) - 1
[1] "2012-10-31"
和月初：
som(som(Sys.Date()) - 1)
[1] "2012-10-01"
于 2012-11-07T11:27:28.593 回答
30
使用lubridate它是小菜一碟：
library(lubridate)
floor_date(Sys.Date() - months(1), "month")
R中有很多好的库。似乎你需要的一切都已经创建了。
更新后的版本：
library(lubridate)
floor_date(as.Date("2011-03-29"), "month") - months(1)
这一项已更正，以便在 3 月 29 日正常工作。
于 2015-04-07T06:53:04.513 回答
18
你可以使用这个库lubridate，它非常擅长做日期运算。
library(lubridate)
currentDate <-Sys.Date()
# end of previous month:
eopm <- currentDate - days(day(currentDate))
# [1] "2012-10-31"
# start of previous month:
sopm <- currentDate - days(day(currentDate))
sopm <- sopm - days(day(sopm) - 1)
# [1] "2012-10-01"
于 2012-11-07T15:17:17.463 回答
16
lubridate 包的另一个选项是使用回滚功能，正如描述所说，就是这样做的。
回滚将日期更改为上个月的最后一天或该月的第一天。或者，新日期可以保留相同的小时、分钟和秒信息。
library(lubridate)
currentDate <- Sys.Date()
end_last_month <- rollback(currentDate)
init_last_month <- rollback(end_last_month, roll_to_first = TRUE)
于 2016-03-29T18:51:20.290 回答
3
上个月开始日期：
format(Sys.Date() - 30, '%Y-%m-01')
上个月结束日期：
as.Date(format(Sys.Date(), '%Y-%m-01')) - 1
于 2016-11-06T21:32:22.147 回答
1
用于timeperiodsR获取任何时期的开始和结束日期。
# install.packages("timeperiodsR")
timeperiodsR::previous_month()
于 2019-10-03T08:38:02.937 回答
0
该解决方案考虑了这样一个事实，即当您从“2022-03-01”中减去 30 天时，您会在 1 月而不是 2 月到达。
# Get end date of previous month
end <- (as.Date(format(Sys.Date(), "%Y-%m-01")) - 1)
# Get start date of previous month after knowing end date
start <- as.Date(format(end, "%Y-%m-01"))
start
#> [1] "2022-02-01"
end
#> [1] "2022-02-28"
# Works in edge cases where subtracting 30 days
# from the current datewill not give you the previous month
date <- "2022-03-01"
end <- (as.Date(format(date, "%Y-%m-01")) - 1)
#> Error in format.default(date, "%Y-%m-01"): invalid 'trim' argument
# Get start date of previous month after knowing end date
start <- as.Date(format(end, "%Y-%m-01"))
start
#> [1] "2022-02-01"
end
#> [1] "2022-02-28"
由reprex 包于 2022-03-04 创建(v2.0.1)
这是我编写的一个函数，以更灵活的方式解决这个问题，使用可变时间段（日、周、月、年）并且全部在基础 R 中：
calc_previous_date_range <- function(x,
time_period = c("day", "week", "month", "year"),
multiplier = 1,
is_complete = TRUE,
week_start = 1) {
time_period <- match.arg(time_period)
if (multiplier == 0) stop(call. = FALSE, "`multiplier` cannot equal 0")
if (time_period == "day") {
if (is_complete) {
start <- x - multiplier
end <- Sys.Date() - 1
} else {
start <- x - (multiplier - 1)
end <- x
}
} else if (time_period == "week") {
if (is_complete) {
start <- cut(x - (7 * multiplier), breaks = 'week', start.on.monday = week_start)
start <- as.Date(start)
end <- cut(x, breaks = "week", start.on.monday = week_start)
end <- as.Date(end)
end <- end - 1
} else {
start <- cut(x, breaks = 'week', start.on.monday = week_start)
if (multiplier > 0) {
start <- as.Date(start) - (7 * (multiplier - 1))
}
end <- x
}
} else if (time_period == "month") {
if (is_complete) {
end <- as.Date(format(x, "%Y-%m-01")) - 1
start <- as.Date(format(as.Date(end), "%Y-%m-01"))
if (multiplier > 1) {
old_month <- as.numeric(format(start, "%m"))
old_year <- as.numeric(format(start, "%Y"))
# Calc new month
new_month <- format(seq(start, length = multiplier, by = "-1 months")[multiplier], "%m")
# Calc new year
if (multiplier >= old_month) {
new_year <- old_year - (1 + floor(((multiplier - old_month) / 12)))
} else {
new_year <- old_year
}
start <- as.Date(paste0(new_year, "-", new_month, "-01"))
}
} else {
start <- format(x, "%Y-%m-01")
start <- as.Date(start)
if (multiplier > 1) {
old_month <- as.numeric(format(start, "%m"))
old_year <- as.numeric(format(start, "%Y"))
# Calc new month
new_month <- format(seq(start, length = multiplier, by = "-1 months")[multiplier], "%m")
# Calc new year
if (multiplier >= old_month) {
new_year <- old_year - (1 + floor(((multiplier - old_month) / 12)))
} else {
new_year <- old_year
}
start <- as.Date(paste0(new_year, "-", new_month, "-01"))
}
end <- x
}
} else if (time_period == "year") {
if (is_complete) {
end <- as.Date(format(x, "%Y-01-01")) - 1
start <- as.Date(format(as.Date(end), paste0(as.numeric(format(end, "%Y")) - (multiplier - 1), "-01-01")))
} else {
start <- format(x, "%Y-%m-01")
start <- as.Date(start)
if (multiplier > 1) {
old_year <- as.numeric(format(as.Date(start)))
start <- format(start, old_year - (multiplier - 1), "-%m-01")
start <- as.Date(start)
}
end <- x
}
}
c(start, end)
}
一些例子：
# Last 6 days (including partial days, i.e. today)
calc_previous_date_range(Sys.Date(), "day", 6, is_complete = FALSE)
#> [1] "2022-02-27" "2022-03-04"
# Last complete 6 days
calc_previous_date_range(Sys.Date(), "day", 6, is_complete = TRUE)
#> [1] "2022-02-26" "2022-03-03"
# Last 3 weeks (including current week)
calc_previous_date_range(Sys.Date(), "week", 3, is_complete = FALSE)
#> [1] "2022-02-14" "2022-03-04"
# Last 3 complete weeks
calc_previous_date_range(Sys.Date(), "week", 3, is_complete = TRUE)
#> [1] "2022-02-07" "2022-02-27"
# Last 3 complete weeks where week start is Sunday instead of Monday
calc_previous_date_range(Sys.Date(), "week", 3, is_complete = TRUE, week_start = 0)
#> [1] "2022-02-06" "2022-02-26"
# Last month (including current month)
calc_previous_date_range(Sys.Date(), "month", 1, is_complete = FALSE)
#> [1] "2022-03-01" "2022-03-04"
# Last complete month
calc_previous_date_range(Sys.Date(), "month", 1, is_complete = TRUE)
#> [1] "2022-02-01" "2022-02-28"
# Last 6 complete months
# Note that the year is handled properly
calc_previous_date_range(Sys.Date(), "month", 6, is_complete = TRUE)
#> [1] "2021-09-01" "2022-02-28"
# Last year (including current year)
calc_previous_date_range(Sys.Date(), "year", 1, is_complete = FALSE)
#> [1] "2022-03-01" "2022-03-04"
# Last year (excluding current year)
calc_previous_date_range(Sys.Date(), "year", 1, is_complete = TRUE)
#> [1] "2021-01-01" "2021-12-31"
# Last 3 years (excluding current year)
calc_previous_date_range(Sys.Date(), "year", 3, is_complete = TRUE)
#> [1] "2019-01-01" "2021-12-31"
于 2022-03-04T17:39:50.110 回答