Hello R-users
I am new to R and trying to write some functions. I have problems writing
functions that takes a data set as an arguement and uses variables in the data.
I illustrate my problem with a small example below:
sample data #------------------
visual24<-rnorm(30,3,5)
visual52<-rt(30,7)
dats<- data.frame(cbind(visual24,visual52))
remove(visual24, visual52)
# first code
#--------------
st <-function(data,x,y){
rcc<-coef(lm(y~x))
plot(x,y)
abline(rcc[1],rcc[2])
}
st(data=dats,x=dats$visual24,y=dats$visual52)
This code works fine, but with such a code the data as an arguement to the
funtion is not necessary.
However, i wish to write a function that reads the variables from the data
directly.
I tried using the function below but it does not work.
# second code
#------------------
st <-function(data,x,y){
rcc<-coef(lm(data$y~data$x))
plot(data$x,data$y)
abline(rcc[1],rcc[2])
}
st(dats,visual24,visual52)
I wish to inquire if any one has an idea of what i need to adjust in the
function so that it works.
I believe that the referencing $x or $y in the function is not doing the
correct thing.
Better still, will it be a problem if i code the functions as in the first
code above?
I mean given that they will be used to create a library
Best regards
Pryseley
---------------------------------
[[alternative HTML version deleted]]
What is wrong with your first solution:
st <-function(x,y){
## y ... Response
## x ... terms
rcc<-coef(lm(y ~ x))
plot(x,y)
abline(rcc[1],rcc[2])
}
st(dats$visual24,dats$visual52)
Or use attach:
st <-function(data,x,y){
attach(data)
rcc<-coef(lm(x~y))
plot(x,y)
abline(rcc[1],rcc[2])
detach(data)
}
st(dats,visual24,visual52)
Best,
Matthias
> -----Urspr??ngliche Nachricht-----
> Von: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] Im Auftrag von
> Pryseley Assam
> Gesendet: Montag, 30. J??nner 2006 14:14
> An: r-help at stat.math.ethz.ch
> Betreff: [R] Help with R: functions
>
>
>
> Hello R-users
>
> I am new to R and trying to write some functions. I have
> problems writing functions that takes a data set as an
> arguement and uses variables in the data. I illustrate my
> problem with a small example below:
>
> sample data #------------------
> visual24<-rnorm(30,3,5)
> visual52<-rt(30,7)
> dats<- data.frame(cbind(visual24,visual52))
> remove(visual24, visual52)
>
> # first code
> #--------------
> st <-function(data,x,y){
> rcc<-coef(lm(y~x))
> plot(x,y)
> abline(rcc[1],rcc[2])
> }
> st(data=dats,x=dats$visual24,y=dats$visual52)
>
> This code works fine, but with such a code the data as an
> arguement to the funtion is not necessary.
> However, i wish to write a function that reads the
> variables from the data directly.
> I tried using the function below but it does not work.
>
> # second code
> #------------------
> st <-function(data,x,y){
> rcc<-coef(lm(data$y~data$x))
> plot(data$x,data$y)
> abline(rcc[1],rcc[2])
> }
> st(dats,visual24,visual52)
>
> I wish to inquire if any one has an idea of what i need to
> adjust in the function so that it works.
> I believe that the referencing $x or $y in the function is
> not doing the correct thing.
>
> Better still, will it be a problem if i code the functions
> as in the first code above?
> I mean given that they will be used to create a library
>
> Best regards
> Pryseley
>
>
>
>
> ---------------------------------
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read
> the posting guide! http://www.R-project.org/posting-guide.html
>
# Here it is (using the formula interface):
dats <- data.frame(visual24 = rnorm(30, 3, 5),
visual52 = rt(30, 7))
st <- function(formula, data, ...) {
# Just use the formula to specify which variables to use
rcc <- coef(lm(formula, data))
# Make sure to keep only variable used in the data frame
plot(data[ , rev(all.vars(formula))])
# Draw the line. Note the ... that allows to change
#lines features
abline(coef = rcc, ...)
# Return the coefficients invisibly
return(invisible(rcc))
}
st(visual52 ~ visual24, data = dats)
# Change style and color of the line (thanks to '...')
st(visual52 ~ visual24, data = dats, lty = 2, col = "red")
Best,
Philippe Grosjean
Pryseley Assam wrote:> Hello R-users
>
> I am new to R and trying to write some functions. I have problems writing
functions that takes a data set as an arguement and uses variables in the data.
I illustrate my problem with a small example below:
>
> sample data #------------------
> visual24<-rnorm(30,3,5)
> visual52<-rt(30,7)
> dats<- data.frame(cbind(visual24,visual52))
> remove(visual24, visual52)
>
> # first code
> #--------------
> st <-function(data,x,y){
> rcc<-coef(lm(y~x))
> plot(x,y)
> abline(rcc[1],rcc[2])
> }
> st(data=dats,x=dats$visual24,y=dats$visual52)
>
> This code works fine, but with such a code the data as an arguement to
the funtion is not necessary.
> However, i wish to write a function that reads the variables from the
data directly.
> I tried using the function below but it does not work.
>
> # second code
> #------------------
> st <-function(data,x,y){
> rcc<-coef(lm(data$y~data$x))
> plot(data$x,data$y)
> abline(rcc[1],rcc[2])
> }
> st(dats,visual24,visual52)
>
> I wish to inquire if any one has an idea of what i need to adjust in the
function so that it works.
> I believe that the referencing $x or $y in the function is not doing the
correct thing.
>
> Better still, will it be a problem if i code the functions as in the
first code above?
> I mean given that they will be used to create a library
>
> Best regards
> Pryseley
>
>
>
>
> ---------------------------------
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
>
st <- function(data, x, y){
attach(data)
rcc <- coef(lm(y~x))
plot(x,y)
abline(rcc)
detach(data)}
st(data=dats, x=visual24, y=visual52)
Pryseley Assam a ??crit :
>Hello R-users
>
> I am new to R and trying to write some functions. I have problems writing
functions that takes a data set as an arguement and uses variables in the data.
I illustrate my problem with a small example below:
>
> sample data #------------------
> visual24<-rnorm(30,3,5)
> visual52<-rt(30,7)
> dats<- data.frame(cbind(visual24,visual52))
> remove(visual24, visual52)
>
> # first code
> #--------------
> st <-function(data,x,y){
> rcc<-coef(lm(y~x))
> plot(x,y)
> abline(rcc[1],rcc[2])
> }
> st(data=dats,x=dats$visual24,y=dats$visual52)
>
> This code works fine, but with such a code the data as an arguement to the
funtion is not necessary.
> However, i wish to write a function that reads the variables from the data
directly.
> I tried using the function below but it does not work.
>
> # second code
> #------------------
> st <-function(data,x,y){
> rcc<-coef(lm(data$y~data$x))
> plot(data$x,data$y)
> abline(rcc[1],rcc[2])
> }
> st(dats,visual24,visual52)
>
> I wish to inquire if any one has an idea of what i need to adjust in the
function so that it works.
> I believe that the referencing $x or $y in the function is not doing the
correct thing.
>
> Better still, will it be a problem if i code the functions as in the first
code above?
> I mean given that they will be used to create a library
>
> Best regards
> Pryseley
>
>
>
>
>---------------------------------
>
>
> [[alternative HTML version deleted]]
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
>
>
This might be a bit closer to what Pryseley wanted:
st <- function(dat, x, y) {
f <- formula(substitute(y ~ x), env=environment(dat))
plot(f, dat)
abline(lm(f, dat))
}
Note that the variable names in the plot when tested on `dats' as Pryseley
created.
Andy
From: Jacques VESLOT>
> st <- function(data, x, y){
> attach(data)
> rcc <- coef(lm(y~x))
> plot(x,y)
> abline(rcc)
> detach(data)}
>
> st(data=dats, x=visual24, y=visual52)
>
>
>
> Pryseley Assam a ??crit :
>
> >Hello R-users
> >
> > I am new to R and trying to write some functions. I have
> problems writing functions that takes a data set as an
> arguement and uses variables in the data. I illustrate my
> problem with a small example below:
> >
> > sample data #------------------
> > visual24<-rnorm(30,3,5)
> > visual52<-rt(30,7)
> > dats<- data.frame(cbind(visual24,visual52))
> > remove(visual24, visual52)
> >
> > # first code
> > #--------------
> > st <-function(data,x,y){
> > rcc<-coef(lm(y~x))
> > plot(x,y)
> > abline(rcc[1],rcc[2])
> > }
> > st(data=dats,x=dats$visual24,y=dats$visual52)
> >
> > This code works fine, but with such a code the data as an
> arguement to the funtion is not necessary.
> > However, i wish to write a function that reads the
> variables from the data directly.
> > I tried using the function below but it does not work.
> >
> > # second code
> > #------------------
> > st <-function(data,x,y){
> > rcc<-coef(lm(data$y~data$x))
> > plot(data$x,data$y)
> > abline(rcc[1],rcc[2])
> > }
> > st(dats,visual24,visual52)
> >
> > I wish to inquire if any one has an idea of what i need to
> adjust in the function so that it works.
> > I believe that the referencing $x or $y in the function is
> not doing the correct thing.
> >
> > Better still, will it be a problem if i code the functions
> as in the first code above?
> > I mean given that they will be used to create a library
> >
> > Best regards
> > Pryseley
> >
> >
> >
> >
> >---------------------------------
> >
> >
> > [[alternative HTML version deleted]]
> >
> >______________________________________________
> >R-help at stat.math.ethz.ch mailing list
> >https://stat.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
> >
> >
> >
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>
>