DT <- data.table(Id = c(1, 1, 1, 1, 10, 100, 100, 101, 101, 101),
Date = as.Date(c("1997-01-01", "1997-01-02", "1997-01-03", "1997-01-04",
"1997-01-02", "1997-01-02", "1997-01-04", "1997-01-03",
"1997-01-04", "1997-01-04")),
Price = c(29, 25, 14, 26, 30, 16, 13, 62, 12, 6),
IsFirst = c(T,F,F,F,T,T,F,T,F,F))
Id:客户ID; 日期:交易日期; 价格:交易金额; isFirst:TRUE是交易是客户第一.每个客户有1个IsFirst == TRUE,[0,Inf] IsFirst == FALSE.
>DT
Id Date Price IsFirst
1: 1 1997-01-01 29 TRUE
2: 1 1997-01-02 25 FALSE
3: 1 1997-01-03 14 FALSE
4: 1 1997-01-04 26 FALSE
5: 10 1997-01-02 30 TRUE …我有一个data.tables列表,我需要cbind,但是,我只需要最后的X列.
我的数据结构如下:
DT.1 <- data.table(x=c(1,1), y = c("a","a"), v1 = c(1,2), v2 = c(3,4))
DT.2 <- data.table(x=c(1,1), y = c("a","a"), v3 = c(5,6))
DT.3 <- data.table(x=c(1,1), y = c("a","a"), v4 = c(7,8), v5 = c(9,10), v6 = c(11,12))
DT.list <- list(DT.1, DT.2, DT.3)
>DT.list
[[1]]
x y v1 v2
1: 1 a 1 3
2: 1 a 2 4
[[2]]
x y v3
1: 1 a 5
2: 1 a 6
[[3]]
x y v4 v5 v6
1: 1 a …我的数据结构如下:
DT <- data.table(Id = c(1, 1, 1, 1, 10, 100, 100, 101, 101, 101),
Date = as.Date(c("1997-01-01", "1997-01-02", "1997-01-03", "1997-01-04",
"1997-01-02", "1997-01-02", "1997-01-04", "1997-01-03",
"1997-01-04", "1997-01-04")),
group = c(1,1,1,1,1,2,2,2,2,2),
Price.1 = c(29, 25, 14, 26, 30, 16, 13, 62, 12, 6),
Price.2 = c(4, 5, 6, 6, 8, 2, 3, 5, 7, 8))
>DT
Id Date group Price.1 Price.2
1: 1 1997-01-01 1 29 4
2: 1 1997-01-02 1 25 5
3: 1 1997-01-03 1 14 6
4: 1 …我使用的数据集结构如下:
library("data.table")
dt <- data.table(Id = c(1,2,3,4,5,6,7,8), "01.01.2005" = c(10,0,0,0,5,7,7,0),
"02.01.2005" = c(4,5,7,0,0,0,9,9), "03.01.2005" = c(2,3,3,6,7,77,45,0),
"04.01.2005" = c(0,0,0,0,0,0,0,1), "05.01.2005" = c(0,1,1,1,1,0,0,2),
"06.01.2005" = c(45,15,45,54,5,76,67,10), "07.01.2005" = c(0,0,0,0,466,21,832,54),
"08.01.2005" = c(2,3,734,2,3,4,5,6))
>dt
Id 01.01.2005 02.01.2005 03.01.2005 04.01.2005 05.01.2005 06.01.2005 07.01.2005 08.01.2005
1: 1 10 4 2 0 0 45 0 2
2: 2 0 5 3 0 1 15 0 3
3: 3 0 7 3 0 1 45 0 734
4: 4 0 0 6 0 1 54 0 …