在 R 中按 ID 移动一行

Shift one row by ID in R

我有数据框,我想创建一个新变量"Begin1",条件是:如果第二行变量"Begin"小于第一行变量"End",设置由于 ID

重叠,"End" 的值替换了 "Begin"
ID <- c(rep(1,3), rep(3, 5), rep(4,4))
Begin <- c(0,2.5,5, 7,8,7,25,25,10,15,17,20)
End <- c(1.5,3.5,6, 7.5,8,11,29,35, 12,19,21,28)
df <- data.frame(ID, Begin, End)
df
    ID Begin  End
1   1   0.0  1.5
2   1   2.5  3.5
3   1   5.0  6.0
4   3   7.0  7.5
5   3   8.0  8.0
6   3   7.0 11.0**
7   3  25.0 29.0
8   3  25.0 35.0**
9   4  10.0 12.0
10  4  15.0 19.0
11  4  17.0 21.0**
12  4  20.0 28.0**

如果你能看到,行加粗,行 (6,8,11,12)。从 ID 为 3 的第 6 行开始,您会看到 "Begin" = 7.0,它比上一行的 "End" 小,现在我们设置 "Begin1" = 8.0。对于ID为3的第8行,"Begin"=25,比之前的"End"=29小,现在我们设置"Begin1"=29,以此类推。这是输出

   ID Begin Begin1  End
1   1   0.0    0.0  1.5
2   1   2.5    2.5  3.5
3   1   5.0    5.0  6.0
4   3   7.0    7.0  7.5
5   3   8.0    8.0  8.0
6   3   7.0    8.0 11.0**
7   3  25.0   25.0 29.0
8   3  25.0   29.0 35.0**
9   4  10.0   10.0 12.0
10  4  15.0   15.0 19.0
11  4  17.0   19.0 21.0**
12  4  20.0   21.0 28.0**

感谢您的建议

这是更新

ID <- c(rep(1,3), rep(3, 5), rep(4,4))
Group <-c(1,1,2,1,1,1,2,2,1,1,1,2)
Begin <- c(0,2.5,5, 7,8,7,25,25,10,15,17,20)
End <- c(1.5,3.5,6, 7.5,8,11,29,35, 12,19,21,28)
df <- data.frame(ID,Group, Begin, End)

这次想按ID和Group分组,报错data.table。

这是输出

   ID Group Begin  End Begin1
1   1   1   0.0  1.5    0.0
2   1   1   2.5  3.5    2.5
3   1   2   5.0  6.0    5.0
4   3   1   7.0  7.5    7.0
5   3   1   8.0  8.0    8.0
6   3   1   7.0 11.0    8.0
7   3   2  25.0 29.0   25.0
8   3   2  25.0 35.0   29.0
9   4   1  10.0 12.0   35.0
10  4   1  15.0 19.0   15.0
11  4   1  17.0 21.0   19.0
12  4   2  20.0 28.0   20.0**** Right here is not change bc it's group 2

这是 dplyr 包的结果,它可以工作,但是 data.table 不工作

library(dplyr)
df %>%
  group_by(ID, Group) %>% 
  mutate(Begin1 = pmax(Begin, lag(End), na.rm =TRUE))

Source: local data frame [12 x 5]
Groups: ID, Group [6]

      ID Group Begin   End Begin1
    (dbl) (dbl) (dbl) (dbl)  (dbl)
1      1     1   0.0   1.5    0.0
2      1     1   2.5   3.5    2.5
3      1     2   5.0   6.0    5.0
4      3     1   7.0   7.5    7.0
5      3     1   8.0   8.0    8.0
6      3     1   7.0  11.0    8.0
7      3     2  25.0  29.0   25.0
8      3     2  25.0  35.0   29.0
9      4     1  10.0  12.0   10.0
10     4     1  15.0  19.0   15.0
11     4     1  17.0  21.0   19.0
12     4     2  20.0  28.0   20.0**** It works

我们可以使用 data.table

library(data.table)
setDT(df)[, Begin1 := Begin]
i1 <- df[, .I[Begin < shift(End, fill = Begin[1L])], by = ID]$V1
df$Begin1[i1] <- df$End[i1-1]
df
#     ID Begin  End Begin1
# 1:  1   0.0  1.5    0.0
# 2:  1   2.5  3.5    2.5
# 3:  1   5.0  6.0    5.0
# 4:  3   7.0  7.5    7.0
# 5:  3   8.0  8.0    8.0
# 6:  3   7.0 11.0    8.0
# 7:  3  25.0 29.0   25.0
# 8:  3  25.0 35.0   29.0
# 9:  4  10.0 12.0   10.0
#10:  4  15.0 19.0   15.0
#11:  4  17.0 21.0   19.0
#12:  4  20.0 28.0   21.0

或者另一种选择是

setDT(df)[, Begin1 := shift(End), by = ID][!which(Begin < Begin1), Begin1:= Begin]
df
#    ID Begin  End Begin1
# 1:  1   0.0  1.5    0.0
# 2:  1   2.5  3.5    2.5
# 3:  1   5.0  6.0    5.0
# 4:  3   7.0  7.5    7.0
# 5:  3   8.0  8.0    8.0
# 6:  3   7.0 11.0    8.0
# 7:  3  25.0 29.0   25.0
# 8:  3  25.0 35.0   29.0
# 9:  4  10.0 12.0   10.0
#10:  4  15.0 19.0   15.0
#11:  4  17.0 21.0   19.0
#12:  4  20.0 28.0   21.0

或使用dplyr

library(dplyr)
df %>%
    group_by(ID) %>% 
    mutate(Begin1 = pmax(Begin, lag(End), na.rm =TRUE))
#      ID Begin   End Begin1
#   <dbl> <dbl> <dbl>  <dbl>
#1      1   0.0   1.5    0.0
#2      1   2.5   3.5    2.5
#3      1   5.0   6.0    5.0
#4      3   7.0   7.5    7.0
#5      3   8.0   8.0    8.0
#6      3   7.0  11.0    8.0
#7      3  25.0  29.0   25.0
#8      3  25.0  35.0   29.0
#9      4  10.0  12.0   10.0
#10     4  15.0  19.0   15.0
#11     4  17.0  21.0   19.0
#12     4  20.0  28.0   21.0

更新

基于 OP 的新数据

setDT(df)[, Begin1 := shift(End), by = .(ID, Group)][
                   !which(Begin < Begin1), Begin1 := Begin]
df
#     ID Group Begin  End Begin1
#1:  1     1   0.0  1.5    0.0
#2:  1     1   2.5  3.5    2.5
#3:  1     2   5.0  6.0    5.0
#4:  3     1   7.0  7.5    7.0
#5:  3     1   8.0  8.0    8.0
#6:  3     1   7.0 11.0    8.0
#7:  3     2  25.0 29.0   25.0
#8:  3     2  25.0 35.0   29.0
#9:  4     1  10.0 12.0   10.0
#10: 4     1  15.0 19.0   15.0
#11: 4     1  17.0 21.0   19.0
#12: 4     2  20.0 28.0   20.0

使用 data.table 的不同方式。关键如下。

  • 根据ID
  • 计算的by语句
  • shift函数,滞后于End变量与Begin比较
  • pmax 函数,它执行逐元素 max 计算

代码如下:

library(data.table)
dt <- as.data.table(df)
dt[, Begin1 := pmax(Begin, shift(End, type = 'lag'), na.rm = TRUE), by = ID]

这是一种基于 End 列的 lag 使用 ifelse 创建列的基础 R 的方法。

df$Begin1 <- ifelse(df$Begin <= lag(df$End), lag(df$End), df$Begin)
df$Begin1[which(is.na(df$Begin1))] <- df$Begin[which(is.na(df$Begin1))]

> df
   ID Begin  End Begin1
1   1   0.0  1.5    0.0
2   1   2.5  3.5    2.5
3   1   5.0  6.0    5.0
4   3   7.0  7.5    7.0
5   3   8.0  8.0    8.0
6   3   7.0 11.0    8.0
7   3  25.0 29.0   25.0
8   3  25.0 35.0   29.0
9   4  10.0 12.0   35.0
10  4  15.0 19.0   15.0
11  4  17.0 21.0   19.0
12  4  20.0 28.0   21.0