[R] Passing colnames to graphics title

[Uwe Ligges]

Uwe Ligges wrote:

> Laura Quinn wrote:
> 
>> Obviously I have been trying to use the colnames() function!
>>
>> However, when I try to subscript ie:
>>
>> for(i in 1:20){
>> main=paste("Site:",colnames(i),sep="")
>> }


BTW: colnames(i) is the same as colnames(1) in the first iteration of 
your loop. What do you expect colnames(1) to be?

Uwe Ligges


> 
> Example (which you should have provided):
> 
>  # Generate an example-matrix:
>  X <- matrix(1:9, 3)
>  colnames(X) <- letters[1:3]
> 
>  # now try to get histograms of columns using a loop:
>  par(mfrow = c(3, 1))
>  cnames <- colnames(X)
>  for(i in 1:ncol(X)){
>    hist(X[,i], main = paste("Site:", cnames[i], sep=""))
>  }
> 
> Uwe Ligges
> 
> 
>> this doesn't work! I thought that as.character(colnames(i)) or
>> substitute(colnames(i)) might work, but to no avail...
>>
>> Laura Quinn
>> Institute of Atmospheric Science
>> School of Earth and Environment
>> University of Leeds
>> Leeds
>> LS2 9JT
>>
>> tel: +44 113 343 1596
>> fax: +44 113 343 6716
>> mail: laura at env.leeds.ac.uk
>>
>> On Wed, 16 Feb 2005, Uwe Ligges wrote:
>>
>>
>>> Laura Quinn wrote:
>>>
>>>
>>>> Hi,
>>>>
>>>> Just a quick query - if I'm creating a function to produce a number of
>>>> histograms per page of output (one per column from a matrix), how can I
>>>> pass the column name of the matrix into the title (or indeed to form 
>>>> part
>>>> of the x-axis label)?
>>>
>>>
>>>
>>> By extracting them using colnames()?
>>>
>>> Uwe Ligges
>>>
>>>
>>>
>>>
>>>> TIA,
>>>> Laura
>>>>
>>>> Laura Quinn
>>>> Institute of Atmospheric Science
>>>> School of Earth and Environment
>>>> University of Leeds
>>>> Leeds
>>>> LS2 9JT
>>>>
>>>> tel: +44 113 343 1596
>>>> fax: +44 113 343 6716
>>>> mail: laura at env.leeds.ac.uk
>>>>
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>>>
>>>
>>>
> 
>