[R] Pointing to a specific place on the x-axis with an arrow

[David Winsemius]

On Oct 6, 2010, at 5:09 AM, Michael Bedward wrote:

> Hi Josh,
>
> Try this...
>
> mtext(expression(symbol("\255")), side=1, line=0, at=7)

For both Rowlingsons's and Bedward's solutions the request for "as  
large as possible" can be addressed with cex = 5 or some more suitable  
value.

-- 
David.
>
> Michael
>
>
> On 6 October 2010 11:45, Josh B <joshb41 at yahoo.com> wrote:
>> Hi all,
>>
>> I am trying to do something simple, but which is deviling me. I  
>> want to add an
>> up-arrow to the x-axis, pointing to a specific location on the  
>> axis. I want the
>> arrow to be as large as possible.
>>
>> Here is where I'm at with my code:
>>
>> #this part if from the ?plot example:
>> require(stats)
>> plot(cars)
>> lines(lowess(cars))
>> #I am trying to use mtext to add the arrow... but I don't know how  
>> to do it:
>> mtext("?", side = 1, line = 0, at = 7)
>> #that question mark is a place-holder for the arrow. How do I put  
>> an up-arrow
>> there instead of the question mark -- as large as possible?
>>
>> Many thanks to all of you in advance.
>> -----------------------------------
>> Josh Banta, Ph.D
>> Center for Genomics and Systems Biology
>> New York University
>> 100 Washington Square East
>> New York, NY 10003
>> Tel: (212) 998-8465
>> http://plantevolutionaryecology.org
>>
>>
>>
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT