r语言 - 如何获得每个患者的最后测量值

Question

对于这个数据集，我想获得每个个体的最新观测值

ID <- c(1:5)
Age <- c(23,34,26,18,35)
day1 <- c(NA,NA,NA,4,2)
day2 <- c(NA,3,NA,NA,NA)
day3 <- c(2,NA,3,NA,4)
last_value <- c(2,3,3,4,4)
mydata <- data.frame(ID, Age, day1, day2, day3)
ID  Age day1 day2 day3 last_value
1   1   23   NA   NA    2          2
2   2   34   NA    3   NA          3
3   3   26   NA   NA    3          3
4   4   18    4   NA   NA          4
5   5   35    2   NA    4          4

Answer 1

使用dplyr，您可以select()您需要的列，rev()将它们反向排列，然后coalesce()查找每一行的第一个非缺失元素。

library(dplyr)
mydata %>%
mutate(last_value = coalesce(!!!rev(select(., starts_with("day")))))
ID Age day1 day2 day3 last_value
1  1  23   NA   NA    2          2
2  2  34   NA    3   NA          3
3  3  26   NA   NA    3          3
4  4  18    4   NA   NA          4
5  5  35    2   NA    4          4

也与across+do.call:

mydata %>%
mutate(last_value = do.call(coalesce, rev(across(starts_with("day")))))

Answer 2

library(tidyverse)
mydata %>% 
pivot_longer(-c(ID, Age)) %>% 
group_by(ID) %>% 
drop_na() %>% 
mutate(last_value = last(value)) %>% 
pivot_wider(names_from = name, values_from = value)
# A tibble: 5 × 6
# Groups:   ID [5]
ID   Age last_value  day3  day2  day1
<int> <dbl>      <dbl> <dbl> <dbl> <dbl>
1     1    23          2     2    NA    NA
2     2    34          3    NA     3    NA
3     3    26          3     3    NA    NA
4     4    18          4    NA    NA     4
5     5    35          4     4    NA     2

Answer 3

使用base R

mydata$last_value <- apply(mydata[-(1:2)], 1, (x) tail(x[!is.na(x)], 1))

与产出

> mydata
ID Age day1 day2 day3 last_value
1  1  23   NA   NA    2          2
2  2  34   NA    3   NA          3
3  3  26   NA   NA    3          3
4  4  18    4   NA   NA          4
5  5  35    2   NA    4          4

---

或使用exec+coalesce

library(dplyr)
library(purrr)
mydata %>% 
mutate(last_value = exec(coalesce, !!! rlang::syms(names(.)[5:3])))