how do you convert a data frame to a table to send as an email body

I have this data frame:

library(sendmailR)
library(pander)

dput(s)
structure(list(Description = c("ServerA", "ServerB", "ServerC", 
"ServerD", "ServerE", "ServerF"), Value = c("2", "2", "100", 
"100", "80", "20")), .Names = c("Description", "Value"), row.names = c(NA, 
6L), class = "data.frame")

I would like to put this data frame in a nice looking table and email it to some people.

I tried it with pandoc but the table looks very plain:

 t<-pandoc.table.return(s, caption="Server CPU Utilization")

    from <- "user@example.com"
    to <- c("end_users@example.com")
    subject <- paste(Sys.time()," Servers CPU utilization")
    body <- t                
    mailControl=list(smtpServer="mailhost.example.net")

    sendmail(from=from,to=to,subject=subject,msg=body,control=mailControl)

Is there any other way to format a data frame into nice looking table to send as email? Table has to be in the email body, not as an attachment.

Solution

What do you mean under?

the table looks very plain

You may also opt for some other markdown format for the table, like passing style = 'grid' to pandoc.table.return, if you do not like the default multiline format. Or you mean the table falls apart/looks ugly with a non-monospace font? The result will depend on the e-mail client, so I would rather opt for sending a HTML mail and specifying a monospace font family, or render the table in HTML.

A quick demo for the HTML version:

Initialize the required R packages:
```
library(sendmailR)
library(xtable)
```

Build a HTML body with concatenating the static part with dynamically created HTML table:

msg <- mime_part(paste('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body>', print(xtable(s), type = 'html'), ',</body>
</html>'))

Override the content-type with an undocumented hack:

msg[["headers"]][["Content-Type"]] <- "text/html"

Send the mail to your specified recipient with the given subject:

from    <- '<foo@example.com>'
to      <- '<bar@example.com>'
subject <- 'HTML table in the body'
body    <- list(msg)
sendmail(from, to, subject, body)

Combining the markdown and HTML versions:

msg <- mime_part(paste('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body><div style="font-family: monospace;">', gsub(' ', '&nbsp;', paste(pander.return(s, caption = "Server CPU Utilization", style = 'grid'), collapse = '<br>')), '</div></body>
</html>'))
msg[["headers"]][["Content-Type"]] <- "text/html"
sendmail(from, to, subject, list(msg))

The trick here is to set the font-family to monospace with inline CSS, also replacing all spaces in the document with non-breaking space. Another (and rather more elegnat) workaround might be to put the markdown between pre HTML tags:

msg <- mime_part(paste('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body><pre>', paste(pander.return(s, caption = "Server CPU Utilization", style = 'grid'), collapse = '\n'), '</pre></body>
</html>'))
msg[["headers"]][["Content-Type"]] <- "text/html"
sendmail(from, to, subject, list(msg))