仅当另一列在R中具有良好的值时，才连续列的总和

Question

I currently have a dataframe looking like that (with time in seconds and Zone1 a boolean):

Time Zone1
   1     0
   3     0
   4     1
   5     1
   6     1
   7     0
   9     1
   10    1

I'd like to have the sum of values for successive criteria so I would get something like this:

Time Zone1 TimeInZone
   1     0         NA
   3     0         NA
   4     1          2
   5     1          2
   6     1          2
   7     0         NA
   9     1          1
   10    1          1

So like this

I can't find what to do, how can I deal with that? Thanks.

EDITED: More accurate dataframe

Answer 1

I'm not entirely sure, where the last two rows came from, but here's my take on it:

library(data.table)
df <- data.table(Value=c(3,4,1,1,2), Criteria=c(1,1,2,1,3))
# First, generate a logical vector that indicates if the criterium changed:
df[, changed:=c(TRUE, Criteria[-1] != Criteria[-length(Criteria)])]
# Then, calculate the cumulative sum to get an index:
df[, index:=cumsum(changed)]
# Calculate the sum for each level of index:
df[, Sum:=sum(Value), by=index]
# print everything:
print(df)

Result:

   Value Criteria changed index Sum
1:     3        1    TRUE     1   7
2:     4        1   FALSE     1   7
3:     1        2    TRUE     2   1
4:     1        1    TRUE     3   1
5:     2        3    TRUE     4   2

To have the sum of the last block, use some data.table magic:

setkey(df, index)
nextblocksums <- df[index!=max(index), .(index=index+1,nextBlockSum=Sum)]
df[ nextblocksums , LastBlocksSum:=i.nextBlockSum]