倒计时R

Question

Suppose I have the following dataset:

id1 <- c(1,1,1,1,2,2,2,2,1,1,1,1)
dates <- c("a","a","a","a","b","b","b","b","c","c","c","c")
x <- c(NA,0,NA,NA,NA,NA,0,NA,NA,NA,NA,0)

df <- data.frame(id1,dates,x)

My objective is to have a new column that explicitly tells counts the sequence of observations around 0 for every combination of id1 and dates. This would yield the following outcome:

desired_result <- c(-1,0,1,2,-2,-1,0,1,-3,-2,-1,0)

Any help is appreciated.

Answer 1

library(dplyr)
df %>% 
  group_by(id1, dates) %>% 
  mutate(x = row_number() - which(x == 0))

     id1 dates     x
 1     1 a        -1
 2     1 a         0
 3     1 a         1
 4     1 a         2
 5     2 b        -2
 6     2 b        -1
 7     2 b         0
 8     2 b         1
 9     1 c        -3
10     1 c        -2
11     1 c        -1
12     1 c         0

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With dplyr 1.1.0 :

df %>% 
  mutate(x = row_number() - which(x == 0), .by = dates)