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Spearfisher
Spearfisher

Reputation: 8773

R - Appending data to a data.frame

I have a data set which looks like this:

job_id start_hour duration
   1     14        3
   2     8         2

Job_id: the id of the job

start_hour: the hour at which the job starts

duration: the number of hours required for the job

I would like to turn it into a table where each line represents an hour for the job:

job_id hour
   1   14
   1   15
   1   16
   2   8
   2   9

So I would have for each job, as much lines as the job requires hours to be done.

Is there an elegant way to do this in R?

Many thanks

Upvotes: 3

Views: 128

Answers (2)

MrFlick
MrFlick

Reputation: 206167

This is also possible with simple base functions. First, an input data.frame

#sample data
dd<-data.frame(
    job_id = 1:2, 
    start_hour = c(14, 8), 
    duration = c(3, 2)
)

Now we use Map to walk through each row and expand it to the right size. Then we combine all the newly expanded rows into one data.frame with do.call(rbind,...)

#transformation
do.call(rbind,Map(function(id,start,dur) {
    data.frame(
        job_id=rep(id, dur), 
        hour=seq(from=start, by=1, length.out=dur))
}, dd$job_id, dd$start_hour, dd$duration))

which gives us

  job_id hour
1      1   14
2      1   15
3      1   16
4      2    8
5      2    9

Upvotes: 2

konvas
konvas

Reputation: 14336

One way to do this is using the package plyr (where d is your original data frame)

ddply(d, .(job_id),
    function(d) data.frame(job_id = d$job_id, 
        hour = d$start_hour:(d$start_hour + d$duration -1)))

Upvotes: 3

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