Send emails based on data in tibble

Question

I'm trying to iterate over tibble to send emails from each row and can't get it to work. Here is example:

packages

library(tidyverse)
library(sendmailR)
library(pander)

First create table I want to include to email

tbl <- tibble(A = c(1,2,3),
              B = c(4,5,6),
              C = c(7,8,9))

table <- pander_return(tbl)

Create tibble, each column corresponds to certain information I want to include to email

emails <- tibble(from = c("jane.doe@gm.com", "john.doe@gm.com"),
                 to = c("jane.doe@gm.com", "john.doe@gm.com"),
                 subject = "This is test",
                 greetings = "Happy Christmas",
                 data = list(table, table))

Now I would like to map each column and add it to correct place to sendmail function from sendmailR package. Here is example how I can send 1 email. Only interesting bit is how greetings and table are joined together to create msg field.

from <- "jane.doe@gm.com"
to <- "jane.doe@gm.com"
subject <- "This is test"
msg <- c(greetings, table)

sendmailR::sendmail(from = from, to = to, subject = subject, msg = msg)

So how can I map that emails tibble to sendmail function, so email would be sent by each row.

Answer 1

This is a perfect use case for the pmap function from purrr

You could do the following

pmap( list(emails$from, emails$to, emails$subject, emails$data) 
      , ~sendmailR::sendmail(from = ..1, 
                            to = ..2, 
                            subject = ..3, 
                            msg = ..4))

This creates a list of arguments, then using the ~ we define the function. The ..x represent the order that the arguments appear in the input list.

Full reprex

library(tidyverse)
library(sendmailR)
library(pander)

tbl <- tibble(A = c(1,2,3),
              B = c(4,5,6),
              C = c(7,8,9))

table <- pander_return(tbl)

emails <- tibble(from = c("jane.doe@gm.com", "john.doe@gm.com"),
                 to = c("jane.doe@gm.com", "john.doe@gm.com"),
                 subject = "This is test",
                 greetings = "Happy Christmas",
                 data = list(greetings, table))

pmap( list(emails$from, emails$to, emails$subject, emails$data) 
      , ~sendmailR::sendmail(from = ..1, 
                            to = ..2, 
                            subject = ..3, 
                            msg = ..4))

And just to show it works with a lower stakes function:

pmap( list(emails$from, emails$to, emails$subject, emails$data) 
      , ~paste(..1, 
                            ..2, 
                            ..3))

Outputs:

[[1]]
[1] "jane.doe@gm.com jane.doe@gm.com This is test"

[[2]]
[1] "john.doe@gm.com john.doe@gm.com This is test"