Question

我有以下数据框：

    Date1              Date2            Date3               Date4              Date5 
1    25 April 2005       10 May 2006   28 March 2007   14 November 2007      1 April 2008  
2    25 April 2005       10 May 2006   28 March 2007   14 November 2007      1 April 2008  
3  29 January 2008   4 December 2008    6 April 2009       1 March 2010   NA 
4  29 January 2008   4 December 2008    6 April 2009       1 March 2010   1 February 2010  
5  29 January 2008   4 December 2008    6 April 2009       1 March 2010   1 February 2010  
6  29 January 2008   4 December 2008    6 April 2009       NA             NA

以下载体：

   1 01/09/2004 
   2 20/03/2007 
   3 16/09/2009 
   4 16/09/2009 
   5 15/07/2008 
   6 16/09/2009

我想计算数据框每行中与向量中的日期相同或日期之前的日期。例如，对于第一行，计数应为零，因为所有日期都在向量中的相应日期之后。

任何人都知道如何做到这一点？

这是dput（）命令的输出，这样你们就可以更容易地将数据读入R中进行测试（如果你想）：

数据帧：

structure(c(" 25 April 2005 ", " 25 April 2005 ", " 29 January 2008 ", 
" 29 January 2008 ", " 29 January 2008 ", " 29 January 2008 ", 
" 10 May 2006 ", " 10 May 2006 ", " 4 December 2008 ", " 4 December 2008 ", 
" 4 December 2008 ", " 4 December 2008 ", " 28 March 2007 ", 
" 28 March 2007 ", " 6 April 2009 ", " 6 April 2009 ", " 6 April 2009 ", 
" 6 April 2009 ", " 14 November 2007 ", " 14 November 2007 ", 
" 1 March 2010 ", " 1 March 2010 ", " 1 March 2010 ", " 1 March 2010 ", 
" 1 April 2008 ", " 1 April 2008 ", " 1 February 2010 ", " 1 February 2010 ", 
" 1 February 2010 ", " 1 February 2010 "), .Dim = c(6L, 5L), .Dimnames = list(
    c("1", "2", "3", "4", "5", "6"), c("Rep1", "Rep2", "Rep3", 
    "Rep4", "Rep5")))

载体：

c("01/09/2004", "20/03/2007", "16/09/2009", "16/09/2009", "15/07/2008", 
"16/09/2009")

Answer 1

如果data.frame被称为m和向量v，那么简单

rowSums(m<=v)

应该这样做（这是有效的，因为m由R表示为粘合了以下列的向量，v将被回收）。不过，首先要确保所有日期都是POSIXct或Date s;有关转化本身的信息，请参阅此question。

Answer 2

第一件事：你真的必须把所有东西都变成Dates，这可能有点棘手。我在矩阵中读取数据，将矢量读作vect。然后：

vect <- as.Date(vect,format="%d/%m/%Y")

# Due to the apart nature of the Date class, the normal apply-solutions 
# don't give the result you're looking for.
Data <- as.data.frame(Data)
for (i in 1:ncol(Data)){
    Data[,i] <- as.Date(Data[,i],format="%d %B %Y")
}
> apply(Data,2,"<=",vect)
      Rep1  Rep2  Rep3  Rep4
[1,] FALSE FALSE FALSE FALSE
[2,]  TRUE  TRUE FALSE FALSE
[3,]  TRUE  TRUE  TRUE FALSE
[4,]  TRUE  TRUE  TRUE FALSE
[5,]  TRUE FALSE FALSE FALSE
[6,]  TRUE  TRUE  TRUE FALSE

> rowSums(apply(Data,2,"<=",vect))
[1] 0 2 3 3 1 3

根据外部条件计算一行中的条目数

2 个答案: