How to perform multiple left joins using dplyr in R [duplicate]

Answer 1

You can use nested left_join

 left_join(x, y, by='Flag') %>%
                left_join(., z, by='Flag') 

Or another option would to place all the datasets in a list and use merge from base R with Reduce

Reduce(function(...) merge(..., by='Flag', all.x=TRUE), list(x,y,z))

Or we have join_all from plyr. Here also, we place the dataframes in a list and use the argument type='left' for left join.

library(plyr)
join_all(list(x,y,z), by='Flag', type='left')