Adding multiple tables in Email using mailR (send.mail) - r

Question

I have 3 dataframes say df1, df2, df3 and I want to send it in an email as 3 separate tables with some space between them.
I am able to currently send 1 dataframe as table with below code
library("mailR")
df1 <- read.csv('Adhoc/temp.csv')
final1 <- print(xtable(df1,caption = "Report"), type = "html", include.rownames = FALSE,
caption.placement = getOption("xtable.caption.placement", "top"),
html.table.attributes = getOption("xtable.html.table.attributes","border=1"))
date_of_report<- Sys.Date() - 1
send.mail(from = "no-reply#abc.com",
to = c('xyz.pqr#abc.com'
),
subject = paste('Report', date_of_report, sep=' '),
body = final1,
html = TRUE,
smtp = list(host.name = "aspmx.l.google.com", port = 25),
authenticate = FALSE,
send = TRUE,
debug=TRUE)
I wanted some help so that I can send all the dataframes in one email itself. Currently I send 3 such emails.

Answer 1

Suggested untested Solution: paste multiple pre-formatted tables:
final1 <- print(xtable(df1,caption = "Report"), type = "html", include.rownames = FALSE,
caption.placement = getOption("xtable.caption.placement", "top"),
html.table.attributes = getOption("xtable.html.table.attributes","border=1"))
final2 <- print(xtable(df2,caption = "Report2"), type = "html", include.rownames = FALSE,
caption.placement = getOption("xtable.caption.placement", "top"),
html.table.attributes = getOption("xtable.html.table.attributes","border=1"))
final3 <- print(xtable(df3,caption = "Report3"), type = "html", include.rownames = FALSE,
caption.placement = getOption("xtable.caption.placement", "top"),
html.table.attributes = getOption("xtable.html.table.attributes","border=1"))
final <- paste(final1, final2, final3, sep="\n")
date_of_report<- Sys.Date() - 1
send.mail(from = "no-reply#abc.com",
to = c('xyz.pqr#abc.com'
),
subject = paste('Report', date_of_report, sep=' '),
body = final,
html = TRUE,
smtp = list(host.name = "aspmx.l.google.com", port = 25),
authenticate = FALSE,
send = TRUE,
debug=TRUE)

Answer 2

I think it makes a lot of sense to define a function, here. And then there are a couple of things I would change up for future extensibility.
library(xtable) # This is required for the xtable function and print method
library(mailR)
# Read the data.frames into a list. This makes it easier to add/remove tables later
dfs <- list(
`Report 1` = data.frame(letter = LETTERS[seq_len(5L)],
number = seq_len(5L),
stringsAsFactors = FALSE
),
`Report 2` = data.frame(letter = letters[6L + seq_len(5L)],
number = 6L + seq_len(5L),
stringsAsFactors = FALSE
),
`Report 3` = data.frame(letter = LETTERS[20L:16L],
number = 20L:16L,
stringsAsFactors = FALSE)
)
Now we need to define the function that will format one of our tables. I'm just calling it make_xtable, and I'm giving it two arguments, the first is a data.frame, and the second is a string that will be used as the caption.
make_xtable <- function(df, caption) {
print(
xtable(df, caption = caption),
type = "html",
include.rownames = FALSE,
caption.placement = getOption("xtable.caption.placement", "top"),
html.table.attributes = getOption("xtable.html.table.attributes", "border=1"),
print.results = FALSE # This suppresses the results from printing to the console
)
}
So far we've loaded in our data, and we've defined a process for creating the tables from a given data.frame and caption string, but we still need to actually run each of our tables through the process. Here is where putting our data.frames into a list will come in handy. The family of apply functions will help us run the function on every element of our list, and then paste0 will let us combine the resulting character vector into a character object of length 1.
email_body <-
paste0(
mapply(
make_xtable,
dfs, # The list of data.frames containing our data
names(dfs) # Names attribute of the list of data.frames
),
collapse = "<br \>" # Concatenate using an HTML newline as a separator
)
Then use email_body as the argument body in the send.mail function.