creating dummy variables based on conditions
Hello,
Your data seems to be of class 'matrix'. The following code needs it to
be a data.frame.
dat <- as.data.frame(your input matrix)
res <- do.call(rbind, lapply(split(dat, list(dat$id, dat$year)),
function(x){
x$ans <- if(any(x$var == 1)) 1 else 0
x}))
rownames(res) <- NULL
res
Hope this helps,
Rui Barradas
Em 14-07-2013 12:30, Anup Nandialath escreveu:
Hello everyone,
I have a dataset which includes the first three variables from the demo
data below (year, id and var). I need to create the new variable ans as
follows
If var=1, then for each year (where var=1), i need to create a new dummy
ans which takes the value of 1 for all corresponding id's where an instance
of one was recorded. Sample data with the output is shown below.
year id var ans
[1,] 2010 1 1 1
[2,] 2010 2 0 0
[3,] 2010 1 0 1
[4,] 2010 1 0 1
[5,] 2011 2 1 1
[6,] 2011 2 0 1
[7,] 2011 1 0 0
[8,] 2011 1 0 0
Any help on how to achieve this is much appreciated.
Thanks
Anup
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