Bind two columns of two dataframes into a single dataframe, filling with NA when the values are not equivalent

Question

Imagine I have these two dataframes:

df1 <- data.frame(column_df1 = c("A", "B", "C", "D"))
df2 <- data.frame(column_df2 = c("A", "B", "C", "E"))

I want to merge them so I get a dataframe that has the following structure:

df3  <- data.frame(column_df1 = c("A", "B", "C", "D", NA),
                   column_df2 = c("A", "B", "C", NA, "E"))

Answer 1

Create an id column, then merge:

merge(cbind(id = df1$column_df1, df1),
      cbind(id = df2$column_df2, df2),
      by = "id", all = TRUE)
#   id column_df1 column_df2
# 1  A          A          A
# 2  B          B          B
# 3  C          C          C
# 4  D          D       <NA>
# 5  E       <NA>          E