Dear R-listers,
I am a relatively inexperienced R-user currently migrating from Stata. I
am deeply frustrated by this data manipulation question: I know how I
could do it in Stata, but I cannot make it work in R.
I have a data frame of hospitalization data where each row represents an
admission. I need to know when patients were first discharged, but the
problem is that patients were sometimes transferred between hospital
departments. In my data a transfer looks like a new admission, except
that it has a 'start' date equal to the previous admission's 'stop'
date.
Here is an example:
id <- c(rep("a",4),rep("b",2), rep("c",5), rep("d",1))
start <- c(c(0,6,17,20),c(0,1),c(0,5,10,11,50),c(0))
stop <- c(c(6,12,20,30),c(1,10),c(3,10,11,30,55),c(6))
data <- as.data.frame(cbind(id,start,stop))
data
# id start stop
# 1 a 0 6
# 2 a 6 12
# 3 a 17 20
# 4 a 20 30
# 5 b 0 1
# 6 b 1 10
# 7 c 0 3
# 8 c 5 10
# 9 c 10 11
# 10 c 11 30
# 11 c 50 55
# 12 d 0 6
So, what I want to end up with is this:
id start stop
a 0 12 # This patient was transferred at time 6 and discharged at
time 12. The admission starting at time 17 is therefore irrelevant.
b 0 10
c 0 3
d 0 6
I have tried tons of variations over lapply, sapply, split, for etc.,
all to no avail.
Thank you in advance for any assistance.
Best regards,
Peter Jepsen, MD.
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