R - Excel VLOOKUP equivalent - Lookup, replace [duplicate]

Answer 1

You are performing a join which in R is performed using the function merge

merge(db, df)

Using the dplyr package allows more natural verbs:

library(dplyr)
inner_join(db, df)

or perhaps (if you want non-matches to be shown; see ?left_join for further information):

left_join(db, df)