如何将重复行添加到R中的数据框？

I currently have an edge list in R that looks something like this:

我目前在R中有一个边缘列表，看起来像这样：

From  To   Start      End 
A     B    1/1/2011   1/2/2011
A     F    1/1/2011   1/1/2011
B     G    1/2/2011   1/2/2011 
C     A    1/2/2011   1/6/2011
D     C    1/2/2011   1/3/2011

What I would like to do is create a new edge list in R that looks something like this

我想要做的是在R中创建一个看起来像这样的新边列表

From  To   Time
A     B    1/1/2011
A     B    1/2/2011
A     F    1/1/2011
B     G    1/2/2011
C     A    1/2/2011
C     A    1/3/2011
C     A    1/4/2011
C     A    1/5/2011
C     A    1/6/2011
D     C    1/2/2011
D     C    1/3/2011

In other words, I would like to duplicate the first two columns each row in the first table for each day between the start and end date, inclusive. What would be a good way to do this? Thanks so much for your help!

换句话说，我想在开始日期和结束日期之间的每一天（包括第一个表格）中复制第一个表格中每一行的前两列。这样做有什么好办法？非常感谢你的帮助！

1 个解决方案

#1

The Date class has a seq function (seq.Date) that you can use, or you can use IDate from data.table:

Date类有一个你可以使用的seq函数（seq.Date），或者你可以使用data.table中的IDate：

df = read.table(text = 'From  To   Start      End 
A     B    1/1/2011   1/2/2011
A     F    1/1/2011   1/1/2011
B     G    1/2/2011   1/2/2011 
C     A    1/2/2011   1/6/2011
D     C    1/2/2011   1/3/2011', header = T)

library(data.table)
dt = data.table(df)

dt[, cbind(.SD, seq(as.Date(Start, '%m/%d/%Y'),
                as.Date(End, '%m/%d/%Y'), 1)), by = list(Start,End)]

# or
dt[, cbind(.SD, seq(as.IDate(Start, '%m/%d/%Y'),
                    as.IDate(End, '%m/%d/%Y'), 1)), by = list(Start,End)]
#       Start      End From To         V2
# 1: 1/1/2011 1/2/2011    A  B 2011-01-01
# 2: 1/1/2011 1/2/2011    A  B 2011-01-02
# 3: 1/1/2011 1/1/2011    A  F 2011-01-01
# 4: 1/2/2011 1/2/2011    B  G 2011-01-02
# 5: 1/2/2011 1/6/2011    C  A 2011-01-02
# 6: 1/2/2011 1/6/2011    C  A 2011-01-03
# 7: 1/2/2011 1/6/2011    C  A 2011-01-04
# 8: 1/2/2011 1/6/2011    C  A 2011-01-05
# 9: 1/2/2011 1/6/2011    C  A 2011-01-06
#10: 1/2/2011 1/3/2011    D  C 2011-01-02
#11: 1/2/2011 1/3/2011    D  C 2011-01-03