R connect 2 data frames 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 inner join

merge(x = df1, y = df2, by = "id", 
      all.x=TRUE)[,c("df1_var1", "df1_var2", "df2_var1")]