如何在R中获取日期中的周数

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有一系列数据，跨了好几年，想按周进行汇聚，找出每周的中位数。请问R中有没有类似weekofyear的函数能够返回日期所在是一年中的第几周？

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关键词：Week year 中位数 KOF ear 获取

I wrote a quick function that you can use.

> weekofyear
function(current_date)
{
    t<-as.POSIXlt(current_date)
    t1<-ISOdate(t$year+1900, 1, 1)
    weeks<-difftime(current_date, t1, units="w")
    weeks
}
> weekofyear(as.Date("2007-10-28"))
Time difference of 42.78571 weeks

 

?weekdays

e.g. weekdays(as.Date('2007-10-31'))

no need for custom functions :)

and use functions such as tapply() with median() to fulfill your idea (DO note there's still further work to do before tapply())

以下是引用谢益辉在2007-10-31 14:48:00的发言：

?weekdays

e.g. weekdays(as.Date('2007-10-31'))

no need for custom functions :)

I am not sure it is you or me. But one of us must have trouble understanding Chinese, English or R language...

oh sorry, I misunderstood his words... but actually only a simple operator %/% is needed...

suppose there're n sample points, then (1:n)%/%7 or rep(1:(n%/%7), each=7) is approximately what he wanted (again, using tapply() & median())

chitchatla 发表于 2007-10-30 00:46
I wrote a quick function that you can use.&gt; weekofyearfunction(current_date){&nbsp;&nbsp;&nbsp; t ...

这个算出来的和excel返回的好像有点不一样

1. library(lubridate)
   
2. paste0(year(Sys.Date()),formatC(week(Sys.Date()), flag = '0', width = 2))

复制代码

判断当前日期为哪一年的第几周

小朝 发表于 2017-6-9 11:47
判断当前日期为哪一年的第几周

非常感谢，正在查这个问题

很简单的嘛！
> date<-as.Date("2022/1/20")
> date
[1] "2022-01-20"
> format(date,"%Y-%W")
[1] "2022-03"