Dear R help,
I am fairly new in data management and programming in R, and am trying to write
what is probably a simple loop, but am not having any luck. I have a dataframe
with something like the following (but much bigger):
Dates<-c("12/10/2010","12/10/2010","12/10/2010","13/10/2010", "13/10/2010",
"13/10/2010")
Groups<-c("A","B","B","A","B","C")
data<-data.frame(Dates, Groups)
I would like to create a new column in the dataframe, and give each distinct
date by group a unique identifying number starting with 1, so that the
resulting column would look something like:
ID<-c(1,2,2,3,4,5)
The loop that I have started to write is something like this (but doesn't
work!):
data$ID<-as.number(c())
for(i in unique(data$Dates)){
for(j in unique(data$Groups)){ data$ID[i,j]<-i
i<-i+1
}
}
Am I on the right track?
Any help on this is much appreciated!
Chandra
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