'Count months before reaching value

I want to calculate per id per row how many months there are before reaching the value 1 in a another colomn. I have a couple of thousands IDs en many months to work with.

id period sick
1 1-1-1990 0
1 1-2-1990 0
1 1-3-1990 1
1 1-4-1990 0
2 1-1-1990 0
2 1-2-1990 0
2 1-3-1990 1
2 1-4-1990 0
2 1-5-1990 0

and I would like to have an output like this

id period sick months_until
1 1-1-1990 0 2
1 1-2-1990 0 1 
1 1-3-1990 1 0 
1 1-4-1990 0 -1 
2 1-1-1990 0 2 
2 1-2-1990 0 1 
2 1-3-1990 1 0 
2 1-4-1990 0 -1 
2 1-5-1990 0 -2
rnode.jsmacosnpm


Solution 1:[1]

Using data.table:

setDT(d)[, months_until := month(as.Date(period, "%d-%m-%Y"))[ sick == 1 ] - seq_len(.N), by = id][]
#    id   period sick months_until
# 1:  1 1-1-1990    0            2
# 2:  1 1-2-1990    0            1
# 3:  1 1-3-1990    1            0
# 4:  1 1-4-1990    0           -1
# 5:  2 1-1-1990    0            2
# 6:  2 1-2-1990    0            1
# 7:  2 1-3-1990    1            0
# 8:  2 1-4-1990    0           -1
# 9:  2 1-5-1990    0           -2

Solution 2:[2]

Here is another idea without using any libraries and utilising seq() by creating a custom function, i.e.

f1 <- function(x){
  i1 <- which(x == 1) - 1
  i2 <- i1 - (length(x) - 1)
  seq(i1, i2)
}

df$new <- with(df, ave(sick, id, FUN = f1))

> df
  id   period sick new
1  1 1-1-1990    0   2
2  1 1-2-1990    0   1
3  1 1-3-1990    1   0
4  1 1-4-1990    0  -1
5  2 1-1-1990    0   2
6  2 1-2-1990    0   1
7  2 1-3-1990    1   0
8  2 1-4-1990    0  -1
9  2 1-5-1990    0  -2

Solution 3:[3]

As stated here, you might want to use "n" a node version manager for UNIX based systems.

How to change to an older version of Node.js

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 zx8754
Solution 2
Solution 3 Ryan Baker

Related Questions