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

[David Winsemius]

On Oct 6, 2010, at 9:03 AM, Josh B wrote:

> Dear Michael,
>
> Thanks very much. I have a follow-up question: how did you know that  
> symbol 255
> is the up-arrow?

?plomath # includes reference to :

http://www.stat.auckland.ac.nz/~paul/R/CM/AdobeSym.html


>
> Josh
> ________________________________
> From: Michael Bedward <michael.bedward at gmail.com>
>
> Cc: R Help <r-help at r-project.org>
> Sent: Wed, October 6, 2010 5:09:48 AM
> Subject: Re: [R] Pointing to a specific place on the x-axis with an  
> arrow
>
> Hi Josh,
>
> Try this...
>
> mtext(expression(symbol("\255")), side=1, line=0, at=7)
>
> Michael
>
>
>
>> 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