printing difftime summary

d <- data.frame(Num=1:5, Date=as.Date("2012-11-26")+(0:4), Delta=diff(as.Date("2012-11-26")+2^(0:5)))
summary(d)

summary(d$Delta)

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of Sam Steingold
Sent: Monday, November 26, 2012 2:20 PM
To: r-help at r-project.org; David Winsemius
Subject: Re: [R] printing difftime summary

* David Winsemius <qjvafrzvhf at pbzpnfg.arg> [2012-11-26 08:46:35 -0800]:

On Nov 26, 2012, at 7:14 AM, Sam Steingold wrote:

summary(infl), where infl$delay is a difftime vector, prints

...

   delay
string:c("492.00 ms", "18.08 min", "1.77 hrs", "8.20 hrs", "8.13 hrs",
"6.98 days")
secs  :c("     0.5", "  1085.1", "  6370.2", " 29534.4", " 29254.0",
"602949.7")



instead of something like

  delay
  Min.:    492 ms
  1st Qu.: 18.08 min

&c

so, how do I arrange for a proper printing of difftime summary as a
part
of the data frame summary?

If you like a particular format from an existing print method then why
not look it up and copy the code?

methods(print)

the problem is that I cannot figure out which function prints this:

   delay
string:c("492.00 ms", "18.08 min", "1.77 hrs", "8.20 hrs", "8.13 hrs",
"6.98 days")
secs  :c("     0.5", "  1085.1", "  6370.2", " 29534.4", " 29254.0",
"602949.7")

I added cat()s to print.summary.difftime and I do not see them, so it
appears that I have no direct control over how a summary.difftime is
printed as a part of a summary of a data.frame.


--8<---------------cut here---------------start------------->8---
summary.difftime <- function (v, ...) {
  s <- summary(as.numeric(v), ...)
  r <- as.data.frame(sapply(s,difftime2string),stringsAsFactors=FALSE)
  names(r) <- c("string")
  r[[units(v)]] <- s
  class(r) <- c("summary.difftime","data.frame")
  invisible(r)
}
print.summary.difftime <- function (sd, ...) {
  cat("[[[print.summary.difftime]]]\n")
  print(list(...))
  print.data.frame(sd, ...)
}
--8<---------------cut here---------------end--------------->8---

--
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
http://www.childpsy.net/ http://palestinefacts.org http://think-israel.org
http://www.memritv.org http://openvotingconsortium.org http://mideasttruth.com
The force of gravity doubles when acting on a body on a couch.