Skip to content

How to assign text string as object?

5 messages · Ing. Michal Kneifl, Ph.D., Henrique Dallazuanna, Michal Kneifl +1 more

#
I have a problem I cannot get over for a long time. Imagine I have a  
data frame with 17 colums. 16 of them are craniometric variables of  
Cervus elaphus and one contains age.
The data frame has 83 rows.
I want to write a loop which plots the values of each craniometric  
variable against the age. The names of columns are V1, V2, V3, etc...
What I have done till now was writing this:

layout(matrix(1:16,4,4))
plot(V1~AGE)
plot(V2~AGE)
.
.
.
.
etc.
How to assign a string in the loop so that the program understands it  
is an object?
Thank for your help in advance.

Michael
#
Take a look at 'matplot'.  If you want to loop, try

for (i in 1:16) plot(df[[paste("V", i, sep="")]] ~ df$AGE)
On 3/16/08, Ing. Michal Kneifl, Ph.D. <xkneifl at mendelu.cz> wrote:

  
    
#
You can try this also:

sapply(DF[-match("AGE", names(DF))], plot, x=DF$AGE)
On 16/03/2008, Ing. Michal Kneifl, Ph.D. <xkneifl at mendelu.cz> wrote:
--
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O
#
One more question Jim.
What if the names of the columns are not a combination of a letter and an 
integer? Suppose they are just "names" of craniometric characteristics, like 
"nasal length", "orbital width" etc?
Thanks for you reply.

Michael

----- Original Message ----- 
From: "jim holtman" <jholtman at gmail.com>
To: "Ing. Michal Kneifl, Ph.D." <xkneifl at mendelu.cz>
Cc: <r-help at stat.math.ethz.ch>
Sent: Sunday, March 16, 2008 11:44 PM
Subject: Re: [R] How to assign text string as object?
#
I think one of the other solutions suggested a way of doing it if
"AGE" was one of the columns and you wanted to plot against all the
others.  It would probably be done in this fashion:

for (i in names(df)[!(names(df) %in% "AGE")]){
    plot(df$AGE, df[[i]], main=i, type='l')
}
On 3/17/08, Michal Kneifl <xkneifl at mendelu.cz> wrote: