Recoding by an order in r - r

Question

I have a data recoding puzzle. Here is how my sample data looks like:
df <- data.frame(
id = c(1,1,1,1,1,1,1, 2,2,2,2,2,2, 3,3,3,3,3,3,3),
scores = c(0,1,1,0,0,-1,-1, 0,0,1,-1,-1,-1, 0,1,0,1,1,0,1),
position = c(1,2,3,4,5,6,7, 1,2,3,4,5,6, 1,2,3,4,5,6,7),
cat = c(1,1,1,1,1,0,0, 1,1,1,0,0,0, 1,1,1,1,1,1,1))
id scores position cat
1 1 0 1 1
2 1 1 2 1
3 1 1 3 1
4 1 0 4 1
5 1 0 5 1
6 1 -1 6 0
7 1 -1 7 0
8 2 0 1 1
9 2 0 2 1
10 2 1 3 1
11 2 -1 4 0
12 2 -1 5 0
13 2 -1 6 0
14 3 0 1 1
15 3 1 2 1
16 3 0 3 1
17 3 1 4 1
18 3 1 5 1
19 3 0 6 1
20 3 1 7 1
There are three ids in the dataset and rows were ordered by a positon variable. For each id, the first row after the scores start by -1 needs to be 0, and the cat variable needs to be 1. For example, for id=1, the first row would be 6th position and in that row, score should be 0 and the cat variable needs to 1. For those ids do not have scores=-1, I keep them as they are.
The desired output should look like below:
id scores position cat
1 1 0 1 1
2 1 1 2 1
3 1 1 3 1
4 1 0 4 1
5 1 0 5 1
6 1 0 6 1
7 1 -1 7 0
8 2 0 1 1
9 2 0 2 1
10 2 1 3 1
11 2 0 4 1
12 2 -1 5 0
13 2 -1 6 0
14 3 0 1 1
15 3 1 2 1
16 3 0 3 1
17 3 1 4 1
18 3 1 5 1
19 3 0 6 1
20 3 1 7 1
Any recommendations??
Thanks

Answer 1

This may be what you are after
df %>%
group_by(id) %>%
mutate(i = which(scores == -1)[1]) %>% # find the first row == -1
mutate(scores = case_when(position == i & scores !=0 ~ 0, T ~ scores), # update the score using position & i
cat = ifelse(scores == -1,0,1)) %>% # then update cat
select (-i) # remove I

Answer 2

After trying a few things and getting ideas from #Ricky and #e.matt, I came up with a solution.
df %>%
filter(scores == -1) %>% # keep cases where var = 1
distinct(id, .keep_all = T) %>% # keep distinct cases based on group
mutate(first = 1) %>% # create first column
right_join(df, by=c("id","scores","position","cat")) %>% # join back original dataset
mutate(first = coalesce(first, 0)) %>% # replace NAs with 0
mutate(scores = case_when(
first == 1 ~ 0,
TRUE~scores)) %>%
mutate(cat = case_when(
first == 1 ~ 1,
TRUE~cat))
This provides my desired output.
id scores position cat first
1 1 0 1 1 0
2 1 1 2 1 0
3 1 1 3 1 0
4 1 0 4 1 0
5 1 0 5 1 0
6 1 0 6 1 1
7 1 -1 7 0 0
8 2 0 1 1 0
9 2 0 2 1 0
10 2 1 3 1 0
11 2 0 4 1 1
12 2 -1 5 0 0
13 2 -1 6 0 0
14 3 0 1 1 0
15 3 1 2 1 0
16 3 0 3 1 0
17 3 1 4 1 0
18 3 1 5 1 0
19 3 0 6 1 0
20 3 1 7 1 0

Answer 3

here is a data.table oneliner
library( data.table )
setDT(df)
df[ df[, .(cumsum( scores == -1 ) == 1), by = .(id)]$V1, `:=`( scores = 0, cat = 1) ]
# id scores position cat
# 1: 1 0 1 1
# 2: 1 1 2 1
# 3: 1 1 3 1
# 4: 1 0 4 1
# 5: 1 0 5 1
# 6: 1 0 6 1
# 7: 1 -1 7 0
# 8: 2 0 1 1
# 9: 2 0 2 1
# 10: 2 1 3 1
# 11: 2 0 4 1
# 12: 2 -1 5 0
# 13: 2 -1 6 0
# 14: 3 0 1 1
# 15: 3 1 2 1
# 16: 3 0 3 1
# 17: 3 1 4 1
# 18: 3 1 5 1
# 19: 3 0 6 1
# 20: 3 1 7 1

Answer 4

You could do something along these lines using the dplyr package:
library(dplyr)
df = mutate(df, cat = ifelse(scores == -1, 1, cat),
scores = ifelse(scores == -1, 0, scores))
Using the mutate() function, I am re-assigning the values for the scores and cat fields according to ifelse() conditional statements. For scores, if the score is -1, the value is replaced by 0, otherwise it keeps the score as is. For cat, it also checks if scores is equal to -1, but would assign a value of 1 when the condition is met, or the already existing value of cat when the condition is not met.
EDIT
After our discussion in the comments, I think something along these lines should be helpful (you may have to modify the logic since I don't exactly follow what the desired output is here):
for(i in 1:nrow(df)){
# Check if score is -1
if(df[i, 'scores'] == -1){
# Update values for the next row
df[i+1, 'scores'] <- 0
df[i+1, 'cat'] <- 1
}
}
Sorry that I don't really follow the desired output, hopefully this is helpful in getting you to your answer!