hjw hjw - 3 months ago 46
R Question

Email dataframe as table in email body with SendMailR

I am trying to send a dataframe with SendMailR. I can send it as an attachment with reasonably good formatting. However I would like to send the dataframe in the body of the email. I tried capture.output, print, sprintf but am not even able to get the format close.

e.g. I tried the following syntax

for (i in 1:nrow(df)){
MSG = c(MSG,rownames(df)[1],as.character(unlist(df[i,])),'\n')
}
MSG = sprintf('%-10s',MSG)
sendmail(from,to,subject,msg = list(MSG,attachment1,attachment2 ... ))


In other words, I am thinking that it might be necessary to convert my dataframe into a format with /n and sprintf('s-10%') etc and store it in MSG. Can someone point me in the right direction?

Answer

Although sending HTML mails with sendmailR is not straighforward, but possible based on a mail discussion with the package author last year (thanks again to Olaf Mersmann for his kind help) - with simply overriding the Content-Type header. E.g.:

msg <- mime_part('<!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"/>
  <title>HTML demo</title>
  <style type="text/css">
  </style>
</head>
<body>
<h1>HTML demo</h1>
</body>
</html>')

## Override content type.
msg[["headers"]][["Content-Type"]] <- "text/html"

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

On the other hand, there is no real need for HTML to present tables or a data.frame in a human-readable format. There is e.g. the ascii package or my pander pkg that can turn R objects to markdown. Quick demo:

> library(pander)
> panderOptions('table.split.table', Inf)
> pander(head(iris, 3))

-------------------------------------------------------------------
 Sepal.Length   Sepal.Width   Petal.Length   Petal.Width   Species 
-------------- ------------- -------------- ------------- ---------
     5.1            3.5           1.4            0.2       setosa  

     4.9             3            1.4            0.2       setosa  

     4.7            3.2           1.3            0.2       setosa  
-------------------------------------------------------------------

> pander(head(iris, 3), style = 'grid')


+----------------+---------------+----------------+---------------+-----------+
|  Sepal.Length  |  Sepal.Width  |  Petal.Length  |  Petal.Width  |  Species  |
+================+===============+================+===============+===========+
|      5.1       |      3.5      |      1.4       |      0.2      |  setosa   |
+----------------+---------------+----------------+---------------+-----------+
|      4.9       |       3       |      1.4       |      0.2      |  setosa   |
+----------------+---------------+----------------+---------------+-----------+
|      4.7       |      3.2      |      1.3       |      0.2      |  setosa   |
+----------------+---------------+----------------+---------------+-----------+

If you want to concatenate this to the e-mail body, use pander.return instead that returns character vector instead of writing to the console. And there are some other available table styles, also some useful panderOptions e.g. to set decimal mark, date format etc: http://rapporter.github.io/pander/

Comments