evaluating string variables

Hello!!!

I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)

#define data frame
L <- data.frame(frame=numeric(7), L=numeric(7))
f0<-1/(5*(5-1)) # first variable for computation

#loop over matrices, Open it , calculate property and put into data frame
for(i in 0:6){
        m<-matrix(scan('C:/R/i.mat', n=5*5),5,5, byrow=TRUE) # load matrix
        f1<-geodist(m)
        f2<-sum(colSums(f1$gdist))
        l <-f0*f2
       # Calculate property
        L[i+1, ]<-c(i,l)
      # Fill data frame
}

but the matrix cannot be loaded, because it try to open a file named
"i.mat". I don`t know how to loop with a counter named 'i', and use it
to define the name of the file too. How can i do it? I have not found
the way.

Leonardo

Hello!!!

I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)

#define data frame
L <- data.frame(frame=numeric(7), L=numeric(7))
f0<-1/(5*(5-1)) # first variable for computation

#loop over matrices, Open it , calculate property and put into data 
frame
for(i in 0:6){
m<-matrix(scan('C:/R/i.mat', n=5*5),5,5, byrow=TRUE) # load matrix
f1<-geodist(m)
f2<-sum(colSums(f1$gdist))
l <-f0*f2
      # Calculate property
L[i+1, ]<-c(i,l)
     # Fill data frame
}

but the matrix cannot be loaded, because it try to open a file named
"i.mat". I don`t know how to loop with a counter named 'i', and use 
it
to define the name of the file too. How can i do it? I have not 
found
the way.

Leonardo

Hello!!!

I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)

#define data frame
L <- data.frame(frame=numeric(7), L=numeric(7))
f0<-1/(5*(5-1)) # first variable for computation

#loop over matrices, Open it , calculate property and put into data frame
for(i in 0:6){
m<-matrix(scan('C:/R/i.mat', n=5*5),5,5, byrow=TRUE) # load matrix
f1<-geodist(m)                                                           
f2<-sum(colSums(f1$gdist))                                        
l <-f0*f2                                                            
      # Calculate property
L[i+1, ]<-c(i,l)                                                     
     # Fill data frame
}

but the matrix cannot be loaded, because it try to open a file named
"i.mat". I don`t know how to loop with a counter named 'i', and use it
to define the name of the file too. How can i do it? I have not found
the way.

Leonardo
 

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of 
Leonardo Sepulveda Dur??n
Sent: Friday, August 12, 2005 7:44 AM
To: r-help at stat.math.ethz.ch
Subject: [R] evaluating string variables

Hello!!!

I have a folder (C:/R/) with matrix files, named by number, i.e.
0.mat, 1.mat,...,1250.mat. In this case, they are 5x5 simetric
matrices. I would like to compute a property for each matrix and put
calculated values into a data frame for posterior ploting and
printing. Below there is an example for 7 matrices (0.mat..6.mat)

#define data frame
L <- data.frame(frame=numeric(7), L=numeric(7))
f0<-1/(5*(5-1)) # first variable for computation

#loop over matrices, Open it , calculate property and put 
into data frame
for(i in 0:6){
	m<-matrix(scan('C:/R/i.mat', n=5*5),5,5, byrow=TRUE) # 
load matrix
	f1<-geodist(m)                                          
                 
	f2<-sum(colSums(f1$gdist))                              
          
	l <-f0*f2                                               
             
       # Calculate property
	L[i+1, ]<-c(i,l)                                        
             
      # Fill data frame
}

but the matrix cannot be loaded, because it try to open a file named
"i.mat". I don`t know how to loop with a counter named 'i', and use it
to define the name of the file too. How can i do it? I have not found
the way.
 
Leonardo

Mac OS 10.3.9 R framework  v. 2.1.1

I am attempting to put a fitted curve into each panel of a lattice 
graph, but am failing to do so. I have tried writing a very 
sophisticated function to do so. The function seems to work when used 
with plot(), but does not do so inside a panel function in xyplot().
Any pointers would be appreciated.

#The example data
fact <- gl(2,7)
x <- rep(1:7,2)
y <- c(1,1,2,3,2,3,4,1,2,1,2,3,3,4)
plot(jitter(y/6) ~ x)

# The following user defined function puts a curve (I believe the 
correct one) into the scatterplot
panel.predglm <- function(x, y) {	
	model.trial <- glm(cbind(y,6-y) ~ poly(x,2), 
family=quasibinomial(link="logit"))
	xfit <- seq(1,7, length=21)
	yfit <- predict(model.trial, newdata=data.frame(x=xfit), 
type="response")
	lines(xfit,yfit)  }

panel.predglm(x, y)


# My attempt to use it in a lattice xyplot, however, fails. It draws a 
curve which in most cases is outside the dimensions of the plot. I 
suspect that the prediction is on the scale of the link functions.

library(lattice)
xyplot(y/6 ~ x|fact, ylim=c(0,.8),
panel=function(x, y,...) {
	panel.xyplot(jitter(x),jitter(y))
	panel.predglm(x,y) }
	)

Any thoughts?

Martin Henry H. Stevens wrote:

Mac OS 10.3.9 R framework  v. 2.1.1

I am attempting to put a fitted curve into each panel of a lattice
graph, but am failing to do so. I have tried writing a very
sophisticated function to do so. The function seems to work when used
with plot(), but does not do so inside a panel function in xyplot().
Any pointers would be appreciated.

#The example data
fact <- gl(2,7)
x <- rep(1:7,2)
y <- c(1,1,2,3,2,3,4,1,2,1,2,3,3,4)
plot(jitter(y/6) ~ x)

# The following user defined function puts a curve (I believe the
correct one) into the scatterplot
panel.predglm <- function(x, y) {	
	model.trial <- glm(cbind(y,6-y) ~ poly(x,2),
family=quasibinomial(link="logit"))
	xfit <- seq(1,7, length=21)
	yfit <- predict(model.trial, newdata=data.frame(x=xfit),
type="response")
	lines(xfit,yfit)  }

panel.predglm(x, y)


# My attempt to use it in a lattice xyplot, however, fails. It draws a
curve which in most cases is outside the dimensions of the plot. I
suspect that the prediction is on the scale of the link functions.

library(lattice)
xyplot(y/6 ~ x|fact, ylim=c(0,.8),
panel=function(x, y,...) {
	panel.xyplot(jitter(x),jitter(y))
	panel.predglm(x,y) }
	)

Any thoughts?

Two:

1. The "y" argument in your panel function ranges from 0 to 1 and not 0
to 6 as your plot example assumes.

2. You need to use llines in your panel function and not lines.

Here's a working example:

library(lattice)
fact <- gl(2,7)
x <- rep(1:7,2)
y <- c(1,1,2,3,2,3,4,1,2,1,2,3,3,4)

# The following user defined function puts a curve (I believe the
correct one) into the scatterplot
panel.predglm <- function(x, y) {	
	model.trial <- glm(cbind(y,6-y) ~ poly(x,2),
                          family=quasibinomial(link="logit"))
	xfit <- seq(1, 7, length=21)
	yfit <- predict(model.trial, newdata=data.frame(x=xfit), 
type="response")
	llines(xfit,yfit)
}

xyplot(y/6 ~ x|fact, ylim=c(0,.8),
        panel = function(x, y, ...) {
          panel.xyplot(jitter(x), jitter(y))
          panel.predglm(x, y * 6)
        })