How can multiple columns be merged into one column in R language?

You can combine multiple columns into one using the unite() function. Here is an example:

Assume you have a dataframe called df with three columns col1, col2, and col3, and you want to merge these three columns into one column named combined.

library(dplyr)

df <- data.frame(col1 = c("a", "b", "c"),
                 col2 = c("d", "e", "f"),
                 col3 = c("g", "h", "i"))

df <- unite(df, combined, col1, col2, col3, sep = "-")

The code above will combine col1, col2, and col3 into one column named combined, using “-” as the delimiter. The merged result will be as follows:

  combined
1  a-d-g
2  b-e-h
3  c-f-i

Please note that you need to load the dplyr package before using the unite() function.