返回R中过去的最接近日期或等效日期

我有两个数据帧

周一

和

t日期

，如下所示：

T Dates 
User.ID   tdate
1       11-02-2013
1       04-03-2013
1       16-04-2015
1       03-05-2015
1       05-05-2015
1       11-05-2015
1       29-09-2015
1       26-11-2013
1       28-11-2013
3       01-02-2016
4       22-11-2012
4       25-04-2013
4       29-05-2013



Mondays     
ID  Monday      Closest Date
1   05-09-2016  
1   20-04-2015  
1   27-07-2015  
1   08-06-2015  
1   13-10-2014  
3   16-09-2013  
3   16-02-2015  
3   29-08-2016  
3   26-05-2014  
3   29-02-2016  
3   18-07-2016  
3   22-02-2016  
4   16-11-2015  

lasttxndate <- function(userid, mydate){
+     return(max(subset(tdates$Date.Asked, tdates$User.ID == userid & tdates$Date.Asked <= as.Date(mydate))))
+ }

现在，我想在

tdates

的第3列中为

mondays

中的每个

User.ID

返回过去的最近日期或等效日期。 例如 预期产量为

Mondays       
ID  Monday      Closest Date
1   05-09-2016  29-09-2015
1   20-04-2015  16-04-2015
1   27-07-2015  11-05-2015
1   08-06-2015  11-05-2015
1   13-10-2014  28-11-2013
3   16-09-2013  NA
3   16-02-2015  NA
3   29-08-2016  01-02-2016
3   26-05-2014  NA
3   29-02-2016  01-02-2016
3   18-07-2016  01-02-2016
3   22-02-2016  01-02-2016
4   16-11-2015  29-05-2013

对于ID=1的<代码>和<代码>2016年9月5日星期一<代码>

过去最近的

tdate

是

29-09-2015

，因此它将在

最近日期

列中获取此日期

注意：如果未发现任何交易日期超过或等于周一的日期，则填写

NAs

这必须针对一个非常大的数据集进行，任何关于如何实现这一点的想法。 我已使用自定义功能尝试了此操作，如下所示：

T Dates 
User.ID   tdate
1       11-02-2013
1       04-03-2013
1       16-04-2015
1       03-05-2015
1       05-05-2015
1       11-05-2015
1       29-09-2015
1       26-11-2013
1       28-11-2013
3       01-02-2016
4       22-11-2012
4       25-04-2013
4       29-05-2013



Mondays     
ID  Monday      Closest Date
1   05-09-2016  
1   20-04-2015  
1   27-07-2015  
1   08-06-2015  
1   13-10-2014  
3   16-09-2013  
3   16-02-2015  
3   29-08-2016  
3   26-05-2014  
3   29-02-2016  
3   18-07-2016  
3   22-02-2016  
4   16-11-2015  

lasttxndate <- function(userid, mydate){
+     return(max(subset(tdates$Date.Asked, tdates$User.ID == userid & tdates$Date.Asked <= as.Date(mydate))))
+ }

lasttxndate
#日期转换
周一$周一此代码运行良好：

T.Dates <- data.frame( 
User.ID=c("1","1","1","1","1","1","1","1","1","3","4","4","4"),
tdate=as.Date(c("11-02-2013","04-03-2013","16-04-2015","03-05-2015","05-05-2015","11-05-2015","29-09-2015","26-11-2013","28-11-2013","01-02-2016","22-11-2012","25-04-2013","29-05-2013"),format="%d-%m-%Y"))


Mondays <- data.frame( 
  ID=c("1","1","1","1","1","3","3","3","3","3","3","3","4"),
  Monday=as.Date(c("05-09-2016","20-04-2015","27-07-2015","08-06-2015","13-10-2014","16-09-2013","16-02-2015","29-08-2016","26-05-2014","29-02-2016","18-07-2016","22-02-2016","16-11-2015"),format="%d-%m-%Y"))

Mondays$Closest.Date <- NA
Mondays$Closest.Date <- as.Date(Mondays$Closest.Date, format="%d-%m-%Y")

for(i in 1:nrow(Mondays)){
Mondays[i,"Closest.Date"] <- max(T.Dates$tdate[T.Dates$User.ID==Mondays$ID[i] & T.Dates$tdate <= Mondays[i,"Monday"]])  
}

T.Dates即使是一个小样本的数据对我们来说也很好！：）而且
dput（周一），…
也很有帮助。正如joel.wilson所说：请仅包括理解和再现问题所需的数据。数据缩短，请参阅编辑的问题。请根据您的需求添加预期输出examples@Sotos：已添加输出，请参见。此操作正常，请您解释一下日期[星期一，on=c（“ID”，“星期一”），roll=Inf]
@pankaj关于data.table join，有很多很好的答案。对于滚动连接，请阅读。也请参见此处