R help - Mar 2014 - Beginner: How do I copy the results from a for loop in a csv file?

Hello
I am using 2 for loops to find the difference between all rows of a matrix.
I  need to store it to a csv file. I have written this:
for (i in 0:length(datamat)){
for (j in i+1:length(datamat)){
x<-datamat[i,]-datamat[j,];
y<-as.data.frama(x);
write.csv(y, "dif.csv")
}}

datamat is the original datamatrix and dif is the file i want to copy the
results to.
However, when i open this file, I find it empty. What is it that I'm doing
wrong? Also, can I store the results of this loop in another matrix? If
then, how? I am new to R and not skilled in other programming languages.
Any help is appreciated!
Thank you

	[[alternative HTML version deleted]]

Tena koe

What are you doing wrong?  For one thing not supplying a simple reproducible
example :-)

Try:
set.seed(12)
(tempMat <- matrix(round(100*runif(12), 0), nrow=3))
     [,1] [,2] [,3] [,4]
[1,]    7   27   18    1
[2,]   82   17   64   39
[3,]   94    3    2   81
(diffMat <- apply(tempMat, 2, diff))
     [,1] [,2] [,3] [,4]
[1,]   75  -10   46   38
[2,]   12  -14  -62   42

and then write.csv(diffMat, 'diffMat.csv')

HTH ....

Peter Alspach

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of koushiki sarkar
Sent: Tuesday, 18 March 2014 3:32 p.m.
To: r-help at r-project.org
Subject: [R] Beginner: How do I copy the results from a for loop in a csv file?

Hello
I am using 2 for loops to find the difference between all rows of a matrix.
I  need to store it to a csv file. I have written this:
for (i in 0:length(datamat)){
for (j in i+1:length(datamat)){
x<-datamat[i,]-datamat[j,];
y<-as.data.frama(x);
write.csv(y, "dif.csv")
}}

datamat is the original datamatrix and dif is the file i want to copy the
results to.
However, when i open this file, I find it empty. What is it that I'm doing
wrong? Also, can I store the results of this loop in another matrix? If then,
how? I am new to R and not skilled in other programming languages.
Any help is appreciated!
Thank you

	[[alternative HTML version deleted]]

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---------- Forwarded message ----------
From: koushiki sarkar <koushikisarkars at gmail.com>
Date: Mon, Mar 17, 2014 at 7:32 PM
Subject: [R] Beginner: How do I copy the results from a for loop in a csv file?
To: r-help at r-project.org


Hello
I am using 2 for loops to find the difference between all rows of a matrix.
I  need to store it to a csv file. I have written this:
for (i in 0:length(datamat)){
for (j in i+1:length(datamat)){
x<-datamat[i,]-datamat[j,];
y<-as.data.frama(x);
write.csv(y, "dif.csv")
}}

datamat is the original datamatrix and dif is the file i want to copy the
results to.
However, when i open this file, I find it empty. What is it that I'm doing
wrong? Also, can I store the results of this loop in another matrix? If
then, how? I am new to R and not skilled in other programming languages.
Any help is appreciated!
Thank you

        [[alternative HTML version deleted]]

______________________________________________
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.
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On Mar 17, 2014, at 7:32 PM, koushiki sarkar wrote:
> Hello
> I am using 2 for loops to find the difference between all rows of a matrix.
> I  need to store it to a csv file. I have written this:
> for (i in 0:length(datamat)){
> for (j in i+1:length(datamat)){
> x<-datamat[i,]-datamat[j,];
> y<-as.data.frama(x);
> write.csv(y, "dif.csv")
> }}
> 
> datamat is the original datamatrix and dif is the file i want to copy the
> results to.
> However, when i open this file, I find it empty. What is it that I'm
doing
> wrong?
A) Not supplying a test case.
B) Not realizing the need for parentheses to clarify intended operator
precedence.
C) Indexing by zero.
D) Not realizing that the "length" of a matrix is the product of n and
m
E) Not reporting the complete error message(s).
F) Misspelling `as.data.frame`
G) Not using the 'file' argument to a write function.
H) HTML
I) Possibly:  expecting files to be written with append=TRUE but not using the
append argument.
> Also, can I store the results of this loop in another matrix?
Not really, at least not as stated. The "result" of a for-loop is
NULL. You need to make any assignments to object names using assignments within
the loop.
> If
> then, how? I am new to R and not skilled in other programming languages.
> Any help is appreciated!
> Thank you
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.
David Winsemius
Alameda, CA, USA