# NOT RUN {
# Example 1. A and B have different factor levels
A <- factor(c("A","E","F"))
B <- factor(c("E","F","G"))
v <- c(4,2,0)
lookup(A,B,v)
# Example 2. Merge treatment means back into the raw data
dat <- data.frame(Trt = rep(LETTERS[1:5],2),
x=round(rnorm(10),2))
# Treatment B is missing all values, treatment D missing one value
dat$x[dat$Trt=="B"] <- NA
dat$x[4] <- NA
# Calculate treatment means
TrtMean <- tapply(dat$x, dat$Trt, mean, na.rm=TRUE)
TrtMean
# Merge the means into the original data
dat$TrtMean <- lookup(dat$Trt, names(TrtMean), TrtMean)
# }
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