Replacing a whole column in R [closed]

Answer 1

With assignment:

data$B <- whatever
# or
data[, "B"] <- whatever
# or
data[["B"]] <- whatever

Answer 2

First I set up an example people.csv.

names <- c("Alice", "Bob", "Carol")
ages <- c(18,21,19)
eyecolor <- c("Blue", "Brown", "Brown")
df <- data.frame(names, ages, eyecolor)
write.csv(df, "people.csv")

Then I replace the age column by a height column:

height <- c(160, 180, 170)
df <- read.csv("people.csv")
df[["ages"]] <- height
colnames(df)[colnames(df) == "ages"] <- "height"
write.csv(df, "people.csv")