R help - Jul 2009 - Colors column don't give correct color with plot()

Hey guys,

I'm having trouble getting the correct colors, when they are read from
a csv file. Here's an example:

1 1 black
1 2 green
1 3 green
1 4 black
1 5 peachpuff

Call it blah.csv. Then I ran:

data <- read.csv("blah.csv",header=FALSE,sep="")

and then to plot the data, I ran:

plot(data[,1],data[,2],col=data[,3])

But the output reports a vertical line with colors:

black
red
red
black
green

going up. Is this a bug in R? If so, could someone fix it?

Thanks,
Vivek

My guess is that 
> class(data[,3]) 
gives "factor" as the result, try casting to character if so. 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Vivek Ayer
Sent: Friday, July 24, 2009 1:24 PM
To: r-help at r-project.org
Subject: [R] Colors column don't give correct color with plot()

Hey guys,

I'm having trouble getting the correct colors, when they are read from
a csv file. Here's an example:

1 1 black
1 2 green
1 3 green
1 4 black
1 5 peachpuff

Call it blah.csv. Then I ran:

data <- read.csv("blah.csv",header=FALSE,sep="")

and then to plot the data, I ran:

plot(data[,1],data[,2],col=data[,3])

But the output reports a vertical line with colors:

black
red
red
black
green

going up. Is this a bug in R? If so, could someone fix it?

Thanks,
Vivek

______________________________________________
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.

Not a bug, just another failure to understand what R is doing when it imports
data or to actually look at your data.

By default, R converts strings to factors during the import process, and as you
found that completely changes the results (converts them to numbers, and uses
those to specify colors).
> mydata <- read.table("blah.csv", header=FALSE, sep="
")
> str(mydata)
'data.frame':	5 obs. of  3 variables:
 $ V1: int  1 1 1 1 1
 $ V2: int  1 2 3 4 5
 $ V3: Factor w/ 3 levels "black","green",..: 1 2 2 1 3


Instead, you need:
> str(mydata)
'data.frame':	5 obs. of  3 variables:
 $ V1: int  1 1 1 1 1
 $ V2: int  1 2 3 4 5
 $ V3: chr  "black" "green" "green"
"black" ...

The third column is now a string, and you are all set. You could also use
color numbers directly, instead of names, and avoid any import problem.

Sarah

On Fri, Jul 24, 2009 at 2:23 PM, Vivek Ayer<vivek.ayer at gmail.com>
wrote:
> Hey guys,
>
> I'm having trouble getting the correct colors, when they are read from
> a csv file. Here's an example:
>
> 1 1 black
> 1 2 green
> 1 3 green
> 1 4 black
> 1 5 peachpuff
>
> Call it blah.csv. Then I ran:
>
> data <- read.csv("blah.csv",header=FALSE,sep="")
>
> and then to plot the data, I ran:
>
> plot(data[,1],data[,2],col=data[,3])
>
> But the output reports a vertical line with colors:
>
> black
> red
> red
> black
> green
>
> going up. Is this a bug in R? If so, could someone fix it?
>
> Thanks,
> Vivek
>
-- 
Sarah Goslee
http://www.functionaldiversity.org

Hey guys,

I'm having trouble getting the correct colors, when they are read from
a csv file. Here's an example:

1 1 black
1 2 green
1 3 green
1 4 black
1 5 peachpuff

Call it blah.csv. Then I ran:

data <- read.csv("blah.csv",header=FALSE,sep="")

and then to plot the data, I ran:

plot(data[,1],data[,2],col=data[,3])

But the output reports a vertical line with colors:

black
red
red
black
green

going up. Is this a bug in R? If so, could someone fix it?

Thanks,
Vivek

Isn't a bug,

try this

plot(d[,1],d[,2],col=as.character(d[,3]))

its because d[,3] is a factor.

Or in read.csv:

d <- read.csv("blah.csv",header=FALSE,sep="",
stringsAsFactor = FALSE)

On Fri, Jul 24, 2009 at 3:23 PM, Vivek Ayer <vivek.ayer@gmail.com> wrote:
> Hey guys,
>
> I'm having trouble getting the correct colors, when they are read from
> a csv file. Here's an example:
>
> 1 1 black
> 1 2 green
> 1 3 green
> 1 4 black
> 1 5 peachpuff
>
> Call it blah.csv. Then I ran:
>
> data <- read.csv("blah.csv",header=FALSE,sep="")
>
> and then to plot the data, I ran:
>
> plot(data[,1],data[,2],col=data[,3])
>
> But the output reports a vertical line with colors:
>
> black
> red
> red
> black
> green
>
> going up. Is this a bug in R? If so, could someone fix it?
>
> Thanks,
> Vivek
>
> ______________________________________________
> R-help@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.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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