[R-pkg-devel] Problems with :::

    if (!inherits(x, "ftable")) 
   if(class(x) == "ftable")  ## really really bad
Thank you Martin, for pointing that out!
I was not aware of it yet and changed all occurences in my package and added in note in my R course material.

(This message is mainly an encouragement that some people actually read the mails and act on it, even if not usually replying).

Regards,
Berry
From: maechler at stat.math.ethz.ch
Date: Mon, 1 Feb 2016 09:49:26 +0100
To: kirill.mueller at ivt.baug.ethz.ch
CC: r-package-devel at r-project.org
Subject: Re: [R-pkg-devel] Problems with :::

Kirill M?ller <kirill.mueller at ivt.baug.ethz.ch>
    on Thu, 28 Jan 2016 17:42:12 +0100 writes:

    > On 28.01.2016 14:20, Duncan Murdoch wrote:
    >> If the class is just "mytable", then you'll have to
    >> change it to "ftable" before calling stats::format().
    > Side note: The following will fail, because format.ftable
    > double-checks the class of its argument:

    > format_ftable <- utils::getS3method("format", "ftable")
    > format_ftable(mytable)

    > -Kirill
Well, I don't think it would fail as that does

    if (!inherits(x, "ftable")) 
        stop("'x' must be an \"ftable\" object")

and the OP did mention that his objects were flat tables.

Note that the above is *good style* as opposed to the  "bad"
code I've seen so often in packages (and otherwise) which would
use something like

   if(class(x) == "ftable")  ## really really bad

because that code will work incorrectly for objects with S3
class attribute, say   c("myFtable", "ftable")

Martin

______________________________________________
R-package-devel at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-package-devel

[R-pkg-devel] Problems with :::

Thread (2 messages)