如何在R中使用dplyr :: inner_join多个tbls或data.frames

Question

In R, how can I inner_join multiple tbls or data.frame s effectively?

For example:

devtools::install_github("rstudio/EDAWR")
library(EDAWR)
library(dplyr)
data(songs)
data(artists)
test <- songs
colnames(test) <- c("song2", "name")
inner_join(songs, artists,by="name") %>% inner_join(test,by="name")

There are hundreds test -like data.frames that I want join.

Answer 1

You could collect the data frames in a list and use Reduce :

L <- list(songs, artists, test)
Reduce(inner_join, L)

#   name  plays                song               song2
# 1 John guitar Across the Universe Across the Universe
# 2 John guitar       Come Together Across the Universe
# 3 John guitar Across the Universe       Come Together
# 4 John guitar       Come Together       Come Together
# 5 Paul   bass      Hello, Goodbye      Hello, Goodbye

You can use L <- mget(ls()) (with an optional pattern arg to ls ) to get everything into a list.

---

As @akrun mentioned in the comments, a plyr alternative is:

library(plyr)
join_all(L, type='inner')