[R] What are the color's name in heat.color(5)

[David Winsemius]

On Mar 28, 2012, at 9:08 AM, Kevin Wright wrote:

> They have hex RGB values instead of names:
>
> R> heat.colors(5)

> [1] "#FF0000FF" "#FF5500FF" "#FFAA00FF" "#FFFF00FF" "#FFFF80FF"
>
> Kevin

The first one is the same as 'red' as can be seen by parsing the RGB  
values above:

 > col2rgb("red")
       [,1]
red    255
green    0
blue     0

HC.m < matrix( c( strtoi( substr(heat.colors(5), 2,3), 16L),  
strtoi(substr(heat.colors(5), 4,5), 16L),  
strtoi(substr(heat.colors(5), 6,7), 16L) ), nrow=3, byrow=TRUE)
HC.m
      [,1] [,2] [,3] [,4] [,5]
[1,]  255  255  255  255  255
[2,]    0   85  170  255  255
[3,]    0    0    0    0  128

One of the others 'yellow' is also in named colors:

 > which( apply(col2rgb(colors()) , 2 , function(x) all( x == c(HC.m[, 
2]))) )
integer(0)
 > which( apply(col2rgb(colors()) , 2 , function(x) all( x == c(HC.m[, 
3]))) )
integer(0)
 > which( apply(col2rgb(colors()) , 2 , function(x) all( x == c(HC.m[, 
1]))) )
[1] 552 553
 > which( apply(col2rgb(colors()) , 2 , function(x) all( x == c(HC.m[, 
4]))) )
[1] 652 653
 > which( apply(col2rgb(colors()) , 2 , function(x) all( x == c(HC.m[, 
5]))) )
integer(0)

 > colors()[552: 553]
[1] "red"  "red1"

 > colors()[652:653]
[1] "yellow"  "yellow1"

-- 
David.
>
>
> On Wed, Mar 28, 2012 at 7:24 AM, YN Kim <y2silence at gmail.com> wrote:
>
>> Hi all,
>>
>> I'm trying to using heat.color function in my data visualization.  
>> So, when
>> I set col = heat.color(5), five different colors are displayed from  
>> red to
>> weak yellow.
>>
>> But, now I want to know the color's keys or the names of the  
>> displayed
>> heat.color. For instance, I think one of the five displayed colors  
>> seems to
>> be 'red'. But, I'm not sure whether it is, also I don't know the  
>> color
>> names for the others.
>>
>> How can I know the exact colors name for that like 'red',  
>> 'darkyellow' and
>> so on?
>>
>> Thanks.
>>
>> YN
>>
>>       [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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.
>>
>
>
>
> -- 
> Kevin Wright
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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