how to cumulatively add values in one vector in R

Question

I have a data set that looks like this

id  name    year    job    job2
1   Jane    1980    Worker  0
1   Jane    1981    Manager 1
1   Jane    1982    Manage         


        

Answer 1

@BrodieG's is way better:

The Data

dat <- read.table(text="id  name    year    job    job2
1   Jane    1980    Manager 1
1   Jane    1981    Manager 1
1   Jane    1982    Manager 1
1   Jane    1983    Manager 1
1   Jane    1984    Manager 1
1   Jane    1985    Manager 1
1   Jane    1986    Boss    0
1   Jane    1987    Boss    0
2   Bob     1985    Manager 1
2   Bob     1986    Manager 1
2   Bob     1987    Manager 1
2   Bob     1988    Boss    0
2   Bob     1989    Boss    0
2   Bob     1990    Boss    0
2   Bob     1991    Boss    0
2   Bob     1992    Boss    0", header=TRUE)

#The code:

inds1 <- rle(dat$job2)
inds2 <- cumsum(inds1[[1]])[inds1[[2]] == 1] + 1

ends <- cumsum(inds1[[1]])
starts <- c(1, head(ends + 1, -1))
inds3 <- mapply(":", starts, ends)
dat$id <- rep(1:length(inds3), sapply(inds3, length))
dat <- do.call(rbind, lapply(split(dat[, 1:5], dat$id ), function(x) {
    if(x$job2[1] == 0){ 
        x$cumu_job2 <- rep(0, nrow(x))
    } else { 
        x$cumu_job2 <- 1:nrow(x)
    }
    x
}))


keeps <- dat$job2 > 0
keeps[inds2] <- TRUE
dat2 <- data.frame(dat[keeps, ], row.names = NULL)
dat2

##    id name year     job job2 cumu_job2
## 1   1 Jane 1980 Manager    1         1
## 2   1 Jane 1981 Manager    1         2
## 3   1 Jane 1982 Manager    1         3
## 4   1 Jane 1983 Manager    1         4
## 5   1 Jane 1984 Manager    1         5
## 6   1 Jane 1985 Manager    1         6
## 7   2 Jane 1986    Boss    0         0
## 8   3  Bob 1985 Manager    1         1
## 9   3  Bob 1986 Manager    1         2
## 10  3  Bob 1987 Manager    1         3
## 11  4  Bob 1988    Boss    0         0