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rmagrittr

saveRDS in a pipe %>% and have it return the object

Is there a way to use saveRDS in a pipe %>% chain? 

c(1,2,3) %>% 
saveRDS(file="123.rda") %>% 
mean()

This currently gives an error because saveRDS returns null.

I want saveRDS() to return c(1,2,3)!

Solution

  • We can use the tee (%T>) operator from magrittr

    library(magrittr)
1:3 %T>% 
   saveRDS(file="123.rda") %>%
   mean
#[1] 2

    If we wants to return the same object, use I

    1:3 %T>% 
  saveRDS(file="123.rda") %>%
  I
#[1] 1 2 3

    According to ?"%T>%"

    Pipe a value forward into a function- or call expression and return the original value instead of theresult. This is useful when an expression is used for its side-effect, say plotting or printing.