[R] overlay points on plot

[Spencer Graves]

      Checking the documentation on lists:  help.start() -> "An 
Introduction to R" -> "Lists and data frames" -> ... "It is very 
important to distinguish Lst[[1]] from Lst[1]. [[...]] is the operator 
used to select a single element, whereas [...] is a general subscripting 
operator. Thus the former is the first object in the list Lst, and if it 
is a named list the name is not included. The latter is a sublist of the 
list Lst consisting of the first entry only. If it is a named list, the 
name is transferred to the sublist."

      hope this helps.  spencer graves

femke wrote:

>Brilliant!   Why the double brackets though?
>
>thanks
>
>femke
>
>
>----- Original Message ----- 
>From: <james.holtman at convergys.com>
>To: "femke" <femke at geog.umd.edu>
>Sent: Wednesday, February 18, 2004 1:58 PM
>Subject: Re: [R] overlay points on plot
>
>
>  
>
>>
>>
>>have you tried:
>>
>> points(v[[2]],v[[3]])
>>__________________________________________________________
>>James Holtman        "What is the problem you are trying to solve?"
>>Executive Consultant  --  Office of Technology, Convergys
>>james.holtman at convergys.com
>>+1 (513) 723-2929
>>
>>
>>
>>                      "femke"
>>                      <femke at geog.umd.edu>         To:
>>    
>>
><r-help at stat.math.ethz.ch>
>  
>
>>                      Sent by:                     cc:
>>                      r-help-bounces at stat.m        Subject:  [R] overlay
>>    
>>
>points on plot
>  
>
>>                      ath.ethz.ch
>>
>>
>>                      02/18/2004 13:03
>>
>>
>>
>>
>>
>>
>>
>>Dear R-help list,
>>
>>I'm trying to overlay a number of data objects in a plot.  Following an
>>earlier example on the list I've created an empty plot as follows
>>
>>    
>>
>>>xlim <- range(as.numeric(c("0","10000")))
>>>ylim <- range(as.numeric(c("0","25")) )
>>>plot(NA, xlim=xlim, ylim=ylim, xlab="distance", ylab="semivariance")
>>>      
>>>
>>However when I try to plot something on it, I get the following error:
>>
>>    
>>
>>>points(v[2],v[3])
>>>      
>>>
>>Error in as.double.default(x) : (list) object cannot be coerced to double
>>
>>A sample of my data looks like the following V[2]:
>>
>>       gamma
>>1   0.040000
>>2   0.582500
>>3   1.574545
>>4   7.126500
>>.....
>>
>>and V[3]:
>>
>>        dist
>>1   470.0426
>>2  1045.6365
>>3  1607.1936
>>....
>>
>>
>>Does anyone have any idea how to fix this?
>>
>>Thanks very much,
>>
>>femke
>>             [[alternative HTML version deleted]]
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
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>>PLEASE do read the posting guide!
>>http://www.R-project.org/posting-guide.html
>>
>>
>>
>>    
>>
>
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>R-help at stat.math.ethz.ch mailing list
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>