Re: [R] Macros in R
Others have pointed you to the answer to your question, but both FAQ
7.21 and the assign help page should really have a big banner at the top
saying Here Be Dragons.
Using a loop or other automated procedure to create variables in the
main namespace can cause hard to find bugs, accidentally clobber
existing variables, and other non-fun things.
For this type of thing it is usually best to use a list (or an
environment, but I am more comforatable with lists).
For your example you could do something like:
mymats - list()
for (i in 1:54){
+ myname - paste('mymatrix',i,sep='')
+ mymats[[myname]] - matrix( # insert whatever code you want here
+ }
A big advantage of this approach is that you can then deal with your
list of matricies as a single unit. If you want to delete them, you
just delete the list rather than having to delete 54 individual
matricies. The list can also be saved as a single unit to a file,
passed to another function, etc.
To access a single matrix (for example 'mymatrix5' which is in position
5) you have several options:
mean( mymats[[5]] )
mean( mymats[['mymatrix5']] )
with( mymats, mean(mymatrix5) )
attach(mymats)
mean(mymatrix5) # as long as there is not a mymatrix 5 in the global
environment
detach()
And probably others.
Hope this helps,
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Monika Kerekes
Sent: Sunday, February 25, 2007 9:03 AM
To: r-help@stat.math.ethz.ch
Subject: [R] Macros in R
Dear members,
I have started to work with R recently and there is one thing
which I could not solve so far. I don't know how to define
macros in R. The problem at hand is the following: I want R
to go through a list of 1:54 and create the matrices input1,
input2, input3 up to input54. I have tried the following:
for ( i in 1:54) {
input[i] = matrix(nrow = 1, ncol = 107)
input[i][1,]=datset$variable
}
However, R never creates the required matrices. I have also
tried to type input'i' and input$i, none of which worked. I
would be very grateful for help as this is a basic question
the answer of which is paramount to any further usage of the software.
Thank you very much
Monika
[[alternative HTML version deleted]]
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Macros in R
The FAQ does mention your point already.
On 2/27/07, Greg Snow [EMAIL PROTECTED] wrote:
Others have pointed you to the answer to your question, but both FAQ
7.21 and the assign help page should really have a big banner at the top
saying Here Be Dragons.
Using a loop or other automated procedure to create variables in the
main namespace can cause hard to find bugs, accidentally clobber
existing variables, and other non-fun things.
For this type of thing it is usually best to use a list (or an
environment, but I am more comforatable with lists).
For your example you could do something like:
mymats - list()
for (i in 1:54){
+ myname - paste('mymatrix',i,sep='')
+ mymats[[myname]] - matrix( # insert whatever code you want here
+ }
A big advantage of this approach is that you can then deal with your
list of matricies as a single unit. If you want to delete them, you
just delete the list rather than having to delete 54 individual
matricies. The list can also be saved as a single unit to a file,
passed to another function, etc.
To access a single matrix (for example 'mymatrix5' which is in position
5) you have several options:
mean( mymats[[5]] )
mean( mymats[['mymatrix5']] )
with( mymats, mean(mymatrix5) )
attach(mymats)
mean(mymatrix5) # as long as there is not a mymatrix 5 in the global
environment
detach()
And probably others.
Hope this helps,
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
[EMAIL PROTECTED]
(801) 408-8111
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Monika Kerekes
Sent: Sunday, February 25, 2007 9:03 AM
To: r-help@stat.math.ethz.ch
Subject: [R] Macros in R
Dear members,
I have started to work with R recently and there is one thing
which I could not solve so far. I don't know how to define
macros in R. The problem at hand is the following: I want R
to go through a list of 1:54 and create the matrices input1,
input2, input3 up to input54. I have tried the following:
for ( i in 1:54) {
input[i] = matrix(nrow = 1, ncol = 107)
input[i][1,]=datset$variable
}
However, R never creates the required matrices. I have also
tried to type input'i' and input$i, none of which worked. I
would be very grateful for help as this is a basic question
the answer of which is paramount to any further usage of the software.
Thank you very much
Monika
[[alternative HTML version deleted]]
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Macros in R
The FAQ does mention using a list (and I did not mean to imply that it did not). Personally I think it is a little soft on this point for the following reasons: 1. It mentions lists at the very end, some users may read about the assign function, think that that answers the question that they think they have, and never read on to the end. 2. The phrase often easier seems a soft sell to me, like consider this, not DO IT THIS WAY. 3. It does not point out any of the dangers of using assign and the additional benefits of using lists. 4. The phrase Here Be Dragons is fun to say, and seeing it grabs attention and gets people thinking (except maybe on September 19th, International Talk Like a Pirate Day). And the parenthetical remark on number 4 brings up the obvious addition to the R Infrequently Asked Questions list: Q: Aye, mateys, what be a pirate's favorite statistical package? A: R, of course (but you need to pronounce it R :-). -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 -Original Message- From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] Sent: Tuesday, February 27, 2007 12:11 PM To: Greg Snow Cc: Monika Kerekes; r-help@stat.math.ethz.ch Subject: Re: [R] Macros in R The FAQ does mention your point already. On 2/27/07, Greg Snow [EMAIL PROTECTED] wrote: Others have pointed you to the answer to your question, but both FAQ 7.21 and the assign help page should really have a big banner at the top saying Here Be Dragons. [snip] __ R-help@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 and provide commented, minimal, self-contained, reproducible code.
Re: [R] Macros in R
If I understand the question correctly, I would do this:
for (i in 1:54) assign( paste('input',i,sep='') , matrix(
dataset$variable, nrow=1) )
You now have 54 matrices, named input1, input2, ... input54, each
having 1 row and as many columns as dataset$variable is long.
(also, they're identical, since all are created from the same object,
dataset$variable)
See, of course, the help page for assign() to see why this works.
However, I do wonder, in the bigger picture of what you're trying to
do, whether there isn't a better way. For example, why matrices,
since they all have only one row?
-Don
At 5:02 PM +0100 2/25/07, Monika Kerekes wrote:
Dear members,
I have started to work with R recently and there is one thing which I could
not solve so far. I don't know how to define macros in R. The problem at
hand is the following: I want R to go through a list of 1:54 and create the
matrices input1, input2, input3 up to input54. I have tried the following:
for ( i in 1:54) {
input[i] = matrix(nrow = 1, ncol = 107)
input[i][1,]=datset$variable
}
However, R never creates the required matrices. I have also tried to type
input'i' and input$i, none of which worked. I would be very grateful for
help as this is a basic question the answer of which is paramount to any
further usage of the software.
Thank you very much
Monika
[[alternative HTML version deleted]]
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
--
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
__
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Macros in R
Its a FAQ.
http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-can-I-turn-a-string-into-a-variable_003f
On 2/25/07, Monika Kerekes [EMAIL PROTECTED] wrote:
Dear members,
I have started to work with R recently and there is one thing which I could
not solve so far. I don't know how to define macros in R. The problem at
hand is the following: I want R to go through a list of 1:54 and create the
matrices input1, input2, input3 up to input54. I have tried the following:
for ( i in 1:54) {
input[i] = matrix(nrow = 1, ncol = 107)
input[i][1,]=datset$variable
}
However, R never creates the required matrices. I have also tried to type
input'i' and input$i, none of which worked. I would be very grateful for
help as this is a basic question the answer of which is paramount to any
further usage of the software.
Thank you very much
Monika
[[alternative HTML version deleted]]
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
__
R-help@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
and provide commented, minimal, self-contained, reproducible code.
