Question

如何使用R查找当月的最后一个工作日（例如，星期三）？在下面的代码中，我计算月份，月份日期，月份周和工作日。 2014年1月有5个星期三，但2014年2月只有4个星期三，因此我不能使用max（月中的某个星期）作为过滤器。尽管我更喜欢使用基本的R函数，但是我们还是有任何帮助。

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Answer 1

我认为这就是你所追求的：

DF$last_weekday_o_month <- ave( 
  weekdays(DF$DATE), 
  months(DF$DATE), 
  FUN = function(x) tail(x[ !(x %in% c("Saturday","Sunday")) ], 1) 
)

查找上一个工作日的特定日期....

DF$last_weekdaydate_o_month <- ave( 
  DF$DATE, 
  months(DF$DATE), 
  FUN = function(x) tail(x[ !(weekdays(x) %in% c("Saturday","Sunday")) ], 1) 
)

结果看起来像......

          DATE last_weekday_o_month last_weekdaydate_o_month
1   2014-01-01               Friday               2014-01-31
2   2014-01-02               Friday               2014-01-31
3   2014-01-03               Friday               2014-01-31
4   2014-01-04               Friday               2014-01-31
5   2014-01-05               Friday               2014-01-31
6   2014-01-06               Friday               2014-01-31
...
360 2014-12-26            Wednesday               2014-12-31
361 2014-12-27            Wednesday               2014-12-31
362 2014-12-28            Wednesday               2014-12-31
363 2014-12-29            Wednesday               2014-12-31
364 2014-12-30            Wednesday               2014-12-31
365 2014-12-31            Wednesday               2014-12-31

如果您首先执行此操作，当然可以将last_weekday_o_month计算为weekdays(last_weekdaydate_o_month)。

根据@RichardScriven的建议，有了几个包，这可以更优雅/可读地完成：

library(data.table)
setDT(DF)[, 
  last_weekdaydate_o_month := last(DATE[!chron::is.weekend(DATE)])
, by = month(DATE)]

给出了

           DATE last_weekdaydate_o_month
  1: 2014-01-01               2014-01-31
  2: 2014-01-02               2014-01-31
  3: 2014-01-03               2014-01-31
  4: 2014-01-04               2014-01-31
  5: 2014-01-05               2014-01-31
 ---                                    
361: 2014-12-27               2014-12-31
362: 2014-12-28               2014-12-31
363: 2014-12-29               2014-12-31
364: 2014-12-30               2014-12-31
365: 2014-12-31               2014-12-31

Answer 2

以下是使用dplyr的方法。基本上你按月分组，过滤掉周末＆＃39;天，并返回最后一天（即最大）的工作日。

library(dplyr)

DF <- data.frame(DATE = seq(as.Date("2014-01-01"), as.Date("2014-12-31"), "day"))

DF %>%
  mutate(month = months(DATE), weekday = weekdays(DATE)) %>%
  group_by(month) %>%
  filter(!weekday %in% c("Saturday", "Sunday")) %>%
  summarise(last_weekday = weekdays(max(DATE))) 

Source: local data frame [12 x 2]

       month        last_weekday
1      April           Wednesday
2     August              Friday
3   December           Wednesday
4   February              Friday
5    January              Friday
6       July            Thursday
7       June              Monday
8      March              Monday
9        May              Friday
10  November              Friday
11   October              Friday
12 September             Tuesday

Answer 3

library(lubridate)
x <- seq(as.Date("2007-12-31"), by="1 day", length.out=(Sys.Date() - as.Date("2007-12-31")))
library(plyr)
df <- data.frame(date=x, year=year(x), month=month(x))
df[,"weekday"] <- weekdays(df[,"date"])
df<- df[! df[,"weekday"] %in% c("Saturday", "Sunday"),]
df <- ddply(df, .(year, month), summarize, last=max(date))

R找到最后一个工作日

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