Beginner help about output in R

Thu, Nov 8, 2012 4:09 PM

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of Jean V Adams
Sent: Thursday, November 08, 2012 3:52 PM
To: nicolapon
Cc: r-help at r-project.org
Subject: Re: [R] Beginner help about output in R

Nicolas,

Maybe something like this would work for you.  Put all of your x values
in
a list (or a vector, if your x values are scalars).  Use sapply to loop
through all of your x values, applying the value1() and value2()
functions, and saving the results in a data frame.  Then write the data
frame to a file.

allofmyxs <- list(x1=48, x2=21, x3=1.9)
mydf <- as.data.frame(t(sapply(allofmyxs, function(x) c(value1(x),
value2(x)))))
write.table(mydf, file=output.txt)

Jean

nicolapon <niqo at msn.com> wrote on 11/08/2012 03:14:51 PM:

Dear R experts,

I am a beginner with R and I have a question regarding the output of

function.

Basically, I created 2 functions, value1 and value2, that calculate

two

values, and I would like to print those two values to an output

datafile. I

tryed the following function:

function (x)

{write.table(data.frame(value1(x),value2(x)),file=output.txt)}

My problem is that I would like to calculate those values for

different

values of x and to get one line in the output file per value.
When I use this function for the second time, it erases the value of

the

first try, etc. How can I proceed so that I will add a new line to

the

output at every step instead of deleting the previous line?

Thank you very much for your answers!

Nicolas

That is the approach I was going to suggest.  Put your x values into a vector, x, and then something like this.

I just made up some functions for computing 2 values, then create an x vector of ten values, then a function for computing and writing the values (trying to follow the OP's original request as closely as possible)

# makeup some functions
value1 <- function (z) 1/(1+exp(z))
value2 <- function (z) 1/z^.5

# create some data values
x <- runif(10)

# define write function
myWrite <- function(y,file) write.table(data.frame(value1=value1(y),value2=value2(y)),file)

# call the function t calculate and write out the values 
myWrite(x,"c:/tmp/test.txt")


Hope this is helpful,

Dan

Daniel Nordlund
Olympia, WA 98504-5204

Beginner help about output in R

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