Displaying 20 results from an estimated 3000 matches similar to: "Combinations with restrictions"
2004 Mar 10
3
converting lists got by tapply to dataframes
I have two lists:
xa <- list( X=c(1,2,3), Y=c(4,5,6), Z=c(7,8,9) )
xb <- with( barley, tapply( X=seq(1:nrow(barley)), INDEX=site
, FUN=function(z)yield[z]))
I can convert xa to a dataframe easily with:
as.data.frame(xa)
But if i try the same with xb I get:
as.data.frame(xb)
Error in as.data.frame.default(xb) :
can't coerce array into a data.frame
What
2008 Dec 30
3
Componentwise means of a list of matrices?
Dear useRs,
I have a list, each entry of which is a matrix of constant dimensions.
Is there a good way (i.e., not using a for loop) to apply a mean to each
matrix entry *across list entries*?
Example:
foo <- list(rbind(c(1,2,3),c(4,5,6)),rbind(c(7,8,9),c(10,11,12)))
some.sort.of.apply(foo,FUN=mean)
I'm looking for a componentwise mean across the two entries of foo,
i.e., the
2011 Mar 22
1
assigning a list item using a variable for a name
I have a list.
my.list <- list(Tom=c(1,2,3), Dick=c(4,5,6), Harry=c(7,8,9))
I assign one of the names of the list to a variable.
name <- "Harry"
I can access the value of the list using the variable as follows:
eval(parse(text=paste("my.list$", name, sep="")))
[1] 7 8 9
But how do I change the value of my.list$Harry using the variable name? This
2007 May 16
3
more woes trying to convert a data.frame to a numerical matrix
I have the following csv file:
name,x,y,z
category,delta,gamma,epsilon
a,1,2,3
b,4,5,6
c,7,8,9
I'd like to create a numeric matrix of just the numbers in this csv dataset.
I've tried the following program:
sample.data <- read.csv("sample.csv")
numerical.data <- as.matrix(sample.data[-1,-1])
However, print(numerical.data) returns what appears to be a matrix of
2010 Sep 01
3
standardize columns selectively within a dataframe
Dear all,
I have a dataframe:
df<-dataframe(a=c(1,2,3),b=c(4,5,6),c=c(7,8,9),d=c(10,11,12))
I want to obtain a new dataframe with columns a and b being standardized
((x-mean(x))/sd(x)); the other two columns (c,d) I want to leave
unchanged. What is the best way to achieve this? I have been trying to
use subscripts but did not succeed so far.
Any tips?
Many thanks,
Olga
2010 Apr 22
2
Compare two data frames
I wonder if there is a more efficient way to do this task. Suppose I have two data frames, such as
d1 <- data.frame(x = c(1,2,3), y = c(4,5,6), z = c(7,8,9))
d2 <- d1[, c('y', 'x')]
The first dataframe d1 has more variables than d2 and the variable columns are in a different order.
So, what I want to do is compare the two frames on the variables that are common between
2009 Sep 04
2
transforming a badly organized data base into a list of data frames
Dear R-ers!
I have a badly organized data base in Excel. Once I read it into R it
looks like this (all variables become factors because of many spaces
and other characters in Excel):
2009 Sep 06
1
struggling with "split" function
I am very sorry for such a simple question, but I am struggling with "split".
I have the following data frame:
x<-data.frame(A=c(NA,NA,NA,NA,"split",NA,NA,NA,NA,"split",NA,NA,NA,NA,"split",NA,NA,NA,NA),
2013 Mar 09
3
data.frame with variable-length list
Hello,
I'm trying to create a data frame with three columns, one of which is a
variable-length list. I tried:
df <- data.frame(name = c("a", "b", "c"),
type=c(1, 2, 3),
rtn = c(list(1,2,3), list(4, 5,6), list(7,8,9, 10)
)
)
This would be useful, for example, if the 'rtn' is a variable number of
2011 Mar 26
2
How to deserialize an array from XML
Hi,
to serialize an array to xml we can use:
an_array = [ 1, 2, 3]
an_array.to_xml
But to I can''t find a way to convert back XML to array. I didn''t find a
method Array.from_xml like Hash.from_xml.
Any ideas?
Thanks,
Gustavo
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2010 Dec 14
4
Change primary_key column name
Hi,
after changing a primary key column name, the auto-increment information
(MySQL) and sequence (Oracle) are lost. What is the correct way to rename
primary keys?
Thanks,
Gustavo
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2010 Nov 08
4
Create Matrix of 2 Dim from two vectors
Hello,
I have two data.
x<-c(1, 2, 3)
y<-c(4,5,6)
How do i create matrix of 3 by 3 from this two, such that
(1,4) (1,5) (1,6)
(2,4) (2,5) (2,6)
(3,4) (3,5) (3,6)
I tried some thing like this:
xy <- as.data.frame(c(0,0,0), dim=c(3,3))
for(i in 1:3)
for(j in 1:3)
xy[i][j]<-c(x[i],y[j])
but i got errors..!!!!
any help would appreciate
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2010 Jul 14
1
Watermark with Ruby on Rails
To whom it may concern, a way to create watermarks with ruby on rails,
imagemagick, attachment_fu and mini-magick in Portuguese, but the code is in
English;)
http://www.woompa.blog.br/2010/07/14/adicionando-marca-dagua-nas-suas-imagens-com-imagemagick-e-mini-magick/
Tnks!
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2009 Dec 17
2
Problem with spliting a dataframe values
Hi all,
Hi this is kiran
I am facing a problem to split a dataframe
that is..
i have a string like: "a,b,c|1,2,3|4,5,6|7,8,8"
first I have to split with respect to "|"
I did it with command
unlist(strsplit("a,b,c|1,2,3|4,5,6|7,8,8", "\\,"))
after getting that set i made it as a dataframe and it comes like
a,b,c
1,2,3
4,5,6
7,8,8
now i have to
2011 May 01
2
More detailed Test::Unit error report
Hi,
I''m starting to use Test::Unit to create unit tests for my Rails
Applications/Plugins. I don''t have much experience in Ruby Unit Testing. The
problem is that the output report is very simple and it is very difficult to
discover where is the error. Test::Unit does not show the line number of the
error and the Stack Trace printed using the --trace option does not help
either.
2011 Jul 16
2
Finding all rows of a matrix equal to vector
Hi everyone,
my question might be very trivial, but I could not come up with an answer...
I want to find out how often a matrix contains a certain vector as row:
x1<-c(1,2,3)
x2<-c(1,5,6)
x3<-c(7,8,9)
A<-matrix(c(rep(x1,5),rep(x2,5),rep(x3,5),rep(x1,5)),nrow=20,ncol=3,byrow=T)
How can I find out, how many times x1 is a row of A?
Thanks in advance and best regards,
Sebastian
2010 Aug 01
4
Admin interface for Rails?
Hello folks, I am currently working on a project that has to deliver
an admin interface like the Django''s one, I wanna know if you know/
recommend any gem or plugin for that.
Cheers,
Rodrigo Alves Vieira
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2017 Sep 22
1
update numeric values of list with new values...
Well, that's a bit like driving from Boston to New York by way of Chicago.
See ?structure
test <- list(a=1,b=2,c=3)
new <- c(4,5,6)
test.new <- structure(as.list(new), names=names(test))
test.new
$a
[1] 4
$b
[1] 5
$c
[1] 6
Cheers,
Bert
Bert Gunter
"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka
2005 Feb 14
3
'combinations' in gtools and stack overflow
Dear R-users,
Let me ask about the 'stack overflow' error which I got when I used
the function 'combinations' in "gtools".
The following is what I did:
---------
library(gtools)
options(expressions=1e5)
combinations(500, 3, 1:500)
# or combinations(400, 2, 1:400)
Error: protect(): stack overflow
---------
How can I overcome this error?
Is there perhaps any other
2017 Sep 22
0
update numeric values of list with new values...
Solved it:
test <- list(a=1,b=2,c=3)
new <- c(4,5,6)
hold <- as.list(new)
updated_test <- replace(test,c(1:3),hold)
$a
[1] 4
$b
[1] 5
$c
[1] 6
mean.parms <- as.list(mean.parms)
mm.parms <- replace(far.parms,c(1:length(far.parms)),mean.parms)
On 9/22/2017 10:34 AM, Evan Cooch wrote:
> Suppose I have the following:
>
> test <- list(a=1,b=2,c=3)
>
> I