Hi everyone,
I have the following code that works in data frames taht I would like tow
ork in data.tables . However, I'm not really sure how to go about it.
I basically have the following
names = c("data1", "data2")
frame = data.frame(list(key1=as.integer(c(1,2,3,4,5,6)),
key2=as.integer(c(1,2,3,2,5,6)),data1 = c(3,3,2,3,5,2), data2=
c(3,3,2,3,5,2)))
for(i in 1:length(names)){
frame[, paste(names[i], "flag")] = frame[,names[i]] < 3
}
Now I try with data.table code:
names = c("data1", "data2")
frame = data.table(list(key1=as.integer(c(1,2,3,4,5,6)),
key2=as.integer(c(1,2,3,2,5,6)),data1 = c(3,3,2,3,5,2), data2=
c(3,3,2,3,5,2)))
for(i in 1:length(names)){
frame[, paste(names[i], "flag"), with=F] = as.matrix(frame[,names[i],
with=F] )< 3
}
However, I have to convert to a matrix on the right side and the left side
doesn't work because you can't assign. I've also tried:
names = c("data1", "data2")
frame = data.table(list(key1=as.integer(c(1,2,3,4,5,6)),
key2=as.integer(c(1,2,3,2,5,6)),data1 = c(3,3,2,3,5,2), data2=
c(3,3,2,3,5,2)))
for(i in 1:length(names)){
frame[, list(as.matrix(frame[,names[i], with=F] )< 3) ]
}
but then I lose the other columns and I don't have the correct name for the
new column.
Anyone have any suggestions on the best approach to doing this?
Thanks,
Rob
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