merge two data frames r code example

Example 1: r how to merge data frames

merge(x = df1, y = df2, by = c("Name_tag1", "Name_tag2"), all = TRUE)

Example 2: r merge by two columns

x <- data.frame(k1=c(NA,NA,3,4,5), k2=c(1,NA,NA,4,5), data=1:5)
y <- data.frame(k1=c(NA,2,NA,4,5), k2=c(NA,NA,3,4,5), data=1:5)
merge(x, y, by=c("k1","k2"))