提取每个月的第一个星期一

如何从2010-01-01到2015-12-31提取每个月的第一个星期一？

1> scoa..：

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我们可以使用lubridate,wday测试这是否是星期一,并day测试这是否是该月的第一周:

library(lubridate)
x <- seq(ymd("2010-01-01"),ymd("2015-12-31"),by="1 day")
x[wday(x,label = TRUE) == "Mon" & day(x) <= 7]

或者在base-r(@ DavidArenburg的评论)

x <- seq(as.Date("2010-01-01"), as.Date("2015-12-31"), by = "day")
# You need to adapt "Monday" to the equivalent in your locale
x[weekdays(x) == "Monday" & as.numeric(format(x, "%d")) <= 7]

输出(五个第一结果)

[1] "2010-01-04 UTC" "2010-02-01 UTC" "2010-03-01 UTC" "2010-04-05 UTC" "2010-05-03 UTC" "2010-06-07 UTC"

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或者只是`x < - seq(as.Date("2010-01-01"),as.Date("2015-12-31"),by ="day"); x [weekdays(x)=="Monday"&as.numeric(format(x,"%d"))<= 7]`with base R

2> lukeA..：

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另一个apprach:使用Boost Date_Time库:

library(RcppBDT)
dates <- seq(as.Date("2010-01-01"), as.Date("2015-12-31"), by="1 month")
do.call(c, lapply(dates-1, getFirstDayOfWeekAfter, dow=Mon))
# [1] "2010-01-04" "2010-02-01" "2010-03-01" "2010-04-05" "2010-05-03"...