Attaching unequal rows of 2 datasets in R

Question

I have two datasets that I would like to merge by a common ID variable. One file (df1) has 1.4mil observations while the other (df2) has 20k. Both contain an ID number and what I would like to do is attach all additional variables, or, columns found in df2 to the rows in df1 where client ID vars match, leaving everything else as is. Ideally, I would just like to paste these to the rows in df1 so that ideally remaining rows in my 1.4mil dataset are simply, missing. Something like this

#>   ID_Num   Var1      ID_Num   Var1 Var2

#> 1 23124   252        23124    252    3
#> 2 12312   161        12312    161    2
#> 2 1233    161        12333    161    
#> 2 12345   161        12345    161    5

I have used dplyr's inner_join command but it always adds many many obs. for example when I use it for df 1 = 1.4mil d42 = 20k

df3 <- innerjoin(df1,df2)

df3 ends up being 4.1 mil. I am very confused by this.

If someone could help I would greatly appreciate it!

question from:https://stackoverflow.com/questions/66067440/attaching-unequal-rows-of-2-datasets-in-r

Answer 1

Waitting for answers