Message-ID: <4DD0F70A.9060803@structuremonitoring.com>
Date: 2011-05-16T10:06:02Z
From: Spencer Graves
Subject: Add "See Also: missing" to help('exists')?
In-Reply-To: <19920.58290.687681.804857@stat.math.ethz.ch>
On 5/16/2011 1:43 AM, Martin Maechler wrote:
> SpG> Might it be feasible to add, "See Also: missing"
> SpG> to the help page for "exists"?
>
>
> SpG> Currently, one can spend hours studying the help
> SpG> page for "exists" without getting a clue to the answer
> SpG> to the post copied below.
>
> Yes. I've added such a link now...
> though quite disillusioned with a very vague hope that useRs
> would read the help page so thoroughly ...
>
> Martin Maechler, ETH Zurich
Hi, Martin: Thanks much. I mentioned this because I have looked in
"See Also" for that kind of thing in the past. Of course, I may be the
only person who does this, so this change might not help anyone else.
Best Wishes, Spencer
> SpG> Thanks, Spencer
>
>
> SpG> On 5/14/2011 3:30 AM, David Winsemius wrote:
> >>
> >> On May 14, 2011, at 3:30 AM, utkarshsinghal wrote:
> >>
> >>>
>>> Hi all,
>>> I want to define a function such that one of its argument if passed
>>> do one
>>> thing and if not passed do the second thing.
>> ?missing
>>
>>> So basically, I have to check
>>> whether the argument is passed or not inside the function. I am
>>> trying to
>>> use 'exists' function to do this.
>>>> f = function(a,b){exists("b")}
>>>> f(a=3, b=4)
>>> [1] TRUE
>>> This is working as expected.
>>> But if I do the following:
>>>> f(a=3)
>>> [1] TRUE
>>> Can anybody explain why this function is returning TRUE here.
>>> --
>>> Many thanks,
>>> Utkarsh
>>> ...
>> David Winsemius, MD
>> West Hartford, CT