Reputation: 28457
If one of my tables has multiple values for the time stamp, and the other just one, can I repeat the value of the single item in the multiple values?
For instance:
XTS_A:
2011/01/01 10:00:00,Bar
2011/01/01 10:00:01,Baz
XTS_B:
2011/01/01 10:00:00,A
2011/01/01 10:00:00,B
2011/01/01 10:00:00,C
2011/01/01 10:00:01,B
Merge_Result:
2011/01/01 10:00:00,A,Bar
2011/01/01 10:00:00,B,Bar
2011/01/01 10:00:00,C,Bar
2011/01/01 10:00:01,B,Baz
Reproducible example:
library(zoo)
library(xts)
XTS_A <- structure(c("Bar", "Baz"), .Dim = c(2L, 1L), index = structure(c(1293894000, 1293894001), tzone = "", tclass = c("POSIXt", "POSIXct")), class = c("xts", "zoo"), .indexCLASS = c("POSIXt", "POSIXct"), .indexTZ = "")
XTS_B <- structure(c("A", "B", "C", "B"), .Dim = c(4L, 1L), index = structure(c(1293894000, 1293894000, 1293894000, 1293894001), tzone = "", tclass = c("POSIXt", "POSIXct")), class = c("xts", "zoo"), .indexCLASS = c("POSIXt", "POSIXct"), .indexTZ = "")
Upvotes: 3
Views: 402
Reputation: 72779
What about just filling down afterwards? Somewhat ugly example (uses a loop, but hard to avoid with sequential dependencies like this):
mrg <- merge(XTS_A,XTS_B)
for(r in seq(nrow(mrg)) ) {
if(is.na(mrg[r,1])) {
mrg[r,1] <- mrg[r-1,1]
}
}
> mrg
XTS_A XTS_B
2011-01-01 16:00:00 "Bar" "A"
2011-01-01 16:00:00 "Bar" "B"
2011-01-01 16:00:00 "Bar" "C"
2011-01-01 16:00:01 "Baz" "B"
Joran's suggestion saves typing using the zoo package's fill-down function:
mrg[,1] <- na.locf(as.vector(mrg$XTS_A))
Upvotes: 3