I would like to add a prefix to all columns that result from a left join.
left_join() has the possibility to add a suffix when names are identical between the two tables being joined. But, it does not have an option to always add this suffix even when they are not identically named. And it does not have an option to instead add a prefix.
flights2 <- flights %>% select(year:day, hour, origin, dest, tailnum, carrier)
airports2 <- airports
result <- flights2 %>% left_join(airports2, c("dest" = "faa")) %>% head()
Source: local data frame [6 x 14]
year month day hour origin dest tailnum carrier name
(int) (int) (int) (dbl) (chr) (chr) (chr) (chr) (chr)
1 2013 1 1 5 EWR IAH N14228 UA George Bush Intercontinental
2 2013 1 1 5 LGA IAH N24211 UA George Bush Intercontinental
3 2013 1 1 5 JFK MIA N619AA AA Miami Intl
4 2013 1 1 5 JFK BQN N804JB B6 NA
5 2013 1 1 5 LGA ATL N668DN DL Hartsfield Jackson Atlanta Intl
6 2013 1 1 5 EWR ORD N39463 UA Chicago Ohare Intl
Variables not shown: lat (dbl), lon (dbl), alt (int), tz (dbl), dst (chr)
Here, it is not possible to know, only from the join result, from which original table each column came.
The purpose of adding this prefix is so that column names be reliably calculated from table names and the column names of data loaded in from a relational database. The database structure loaded into and stored in R and naming conventions for the relational database will be used, for example, to identify primary and foreign keys. These will then be used to set up the joins and to later retrieve data from the join results.