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

Question

How do I join multiple dataframes in R using dplyr ?

new <- left_join(x,y, by = "Flag") 

this is the code I am using to left join x and y the code doesn't work for multiple joins

new <- left_join(x,y,z by = "Flag") 

Answer 1

You can use nested left_join

 library(dplyr)  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') 

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As @JBGruber mentioned in the comments, it can also be done via purrr

library(purrr) library(dplyr) purrr::reduce(list(x,y,z), dplyr::left_join, by = 'Flag')