Displaying 20 results from an estimated 10000 matches similar to: "Vector to Matrix transformation"
2007 Jan 24
3
Conversion of column matrix into a vector without duplicates
Hi R,
I have a matrix A,
A=
[,1] [,2]
[1,] a u
[2,] b v
[3,] c x
[4,] d x
[5,] e x
I want to put the 2nd column of this matrix in a vector without
duplicates. i.e., my vector v should be (u, v, x), whose length is 3.
Can anybody help me on this?
Thanks in advance
Shubha.
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2008 Jul 23
18
Simple... but...
Hi R,
If
x=c(1,3,5)
y=c(2,4,6)
I need a vector which is c(1,2,3,4,5,6) from x and y.
How do I do it? I mean the best way....
Thanks, Shubha
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2008 May 13
9
A Very Simple Question
On 5/13/2008 10:27 AM, Yukihiro Ishii wrote:
> Hi Rusers!
>
> I am ashed of asking such a simple question.
>
> X<-matrix(rnorm(24), 4)
> X0<-apply(X,2,mean)
>
> What I want is a matrix which consists of colums such as X[,1]--X0[1].
>
> X-X0 doesn't work.
>
> Perhaps apply function?
scale(X, scale=FALSE)
?scale
> Thanks in advance.
>
>
2008 Jun 04
4
sum of unknown number of matrices
Hi R,
I have a list of matrices. I need to get the sum of all the matrices in
the list.
Example:
a=b=c=d=matrix(1:4,2,2)
l=list(a,b,c,d)
I need:
> a+b+c+d
[,1] [,2]
[1,] 4 12
[2,] 8 16
Something like do.call("+",l) is not working...why is this?
I may not be knowing the number of matrices in the list...
Thanks, Shubha
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2008 Feb 14
3
Transposing by a group variable
Hi R,
Can I transpose a data frame by a particular group variable?
For example:
d=data.frame(group=c(1,1,2,2,2),val=c(6,4,6,3,5))
And my output should be:
data.frame(group=c(1,2),v1=c(6,6),v2=c(4,3),v3=c(NA,5))
Many thanks,
Shubha
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2008 May 13
3
Regular Expressions
Hi R,
Again struck with regular expressions...
Suppose,
S=c("World_is_beautiful", "one_two_three_four","My_book")
I need to extract the last but one element of the strings. So, my output should look like:
Ans=c("is","three","My")
gsub() can do this...but wondering how do I give the regular expression....
2008 Jun 09
3
Overlaying the matrices
Hi R,
I have a matrix,
> x1=matrix(NA,6,6,dimnames=list(letters[1:6],LETTERS[1:6]))
> x1
A B C D E F
a NA NA NA NA NA NA
b NA NA NA NA NA NA
c NA NA NA NA NA NA
d NA NA NA NA NA NA
e NA NA NA NA NA NA
f NA NA NA NA NA NA
> x2=matrix(rpois(9,1),3,3,dimnames=list(c("b","a","f"),c("D","E","F")))
> x2
2008 Jul 23
8
sequential sum of a vector...
Hi R,
Let,
x=1:80
I want to sum up first 8 elements of x, then again next 8 elements of x,
then again another 8 elements..... So, my new vector should look like:
c(36,100,164,228,292,356,420,484,548,612)
I used:
aggregate(x,list(rep(1:10,each=8)),sum)[-1]
or
rowsum(x,group=rep(1:10,each=8))
But without grouping, can I achieve the required? Any other ways of
doing
2008 Jul 08
8
Sum(Random Numbers)=100
Hi R,
I need to generate 50 random numbers (preferably poisson), such that
their sum is equal to 100. How do I do this?
Thank you,
Shubha
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2008 Aug 12
7
Between the values
Hi R,
This is a very trivial one....
C=0.1
I want to check whether my value of C is between 0 and 1 exclusively....
I don't want to use (C>0 & C<1). And I can't use a single statement like
(0<C<1). Is there a between function? Or how do we specify from 0 to 1?
Does %in% help me?
Many Thanks,
Shubha
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2008 Apr 09
11
Number of words in a string
Hi R,
A quick question: How do we find the number of words in a string?
Example:
C="Have a nice day"
And the number of words should be 4. any built in function or?...
Thanks, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
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2008 May 06
2
To preserve the class "Matrix"
Hi,
Suppose
a=matrix(1:9,3,3)
> a
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
Now,
> class(a[1:2,])
[1] "matrix"
> class(a[1:3,])
[1] "matrix"
> class(a[,1:2])
[1] "matrix"
> class(a[,1:3])
[1] "matrix"
But,
> class(a[1,])
[1] "integer"
> class(a[,1])
[1]
2007 Feb 13
5
Fatigued R
Hi R,
Please solve my problem...........
I am extracting Bloomberg data from R, in a loop. R is getting fatigued
by doing this process and gives some errors. I introduced sleep
function. Doing this sometimes I get the results and sometimes not. I
even noticed that if I give complete rest for R (don't open R window)
for 1 day and then run my code with the sleep function, then the
2008 Mar 25
3
Dimensions of a List
Hi R,
I have a list,
l=list(list(c(1,2),c(4,5),c(6,7)),list(c(11,22,33),c(44,55,66)))
> l
[[1]]
[[1]][[1]]
[1] 1 2
[[1]][[2]]
[1] 4 5
[[1]][[3]]
[1] 6 7
[[2]]
[[2]][[1]]
[1] 11 22 33
[[2]][[2]]
[1] 44 55 66
How do I know the dimensions of this list?... In other words, how many
sub-lists, sub-sub-lists etc...are there in l? How do I know this?
2006 Nov 16
5
<RBloomberg Package Problem>
Hi R-Experts,
I'm currently using R 2.4.0 in Windows XP. I'm trying to download data
from Bloomberg using the package "RBloomberg", but it fails to install
the three needed packages "zoo", "chron" and 'Rbloomberg". Moreover I
am not able to find "RBloomberg" package as windows binary in CRAN
site as only for MAC it's given. Please
2010 Jan 03
2
Scores in Dimensions in Correspondence Analysis
Hi R,
I was experimenting with the CA package for correspondence analysis.
data(author)
ca(author)
plot(ca(author))
How can I get the values used by the plot for the two axis for biplot?
In other words, how will I be able to obtain the scores in the
dimensions (which are obtained by PCA) of the graphs? Thanks.
Thanks and Regards,
Shubha
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2006 Dec 02
4
Fwd: Urgent Help in Paste Command
Hi Experts,
I want to see my object as below:
'C:\Program Files\R\R-2.4.0\bin\Rgui.exe'
So I use the paste command. None of the below is working. Could anyone help
me on this?
> paste("'C:\Program Files\R\R-2.4.0\bin\Rgui.exe'")
[1] "'C:Program FilesRR-2.4.0\binRgui.exe'"
> paste("'C:","\","Program
2008 May 14
2
dataframes to a list
Hi R,
I have the data frames, data1, data2....data50. Now I want to put all of
these in a single list. But,
>list(data1, data2,.........data50) is very big to write. How do I then
do it?
Thanks,
Shubha
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2008 Aug 07
3
Downloading Yahoo data
Hi R,
I am trying to download the data from R. I give the below command.
> library(fImport)
> yahooSeries("IBM")
trying URL
'http://chart.yahoo.com/table.csv?s=IBM&a=7&b=08&c=2007&d=7&e=07&f=2008&
g=d&x=.csv'
Error in download.file(url = url, destfile = file, method = method) :
cannot open URL
2010 Apr 24
4
DICE Coefficient of similarity measure
Hi,
I wanted the DICE coefficient (similarity measure for binary variables)
to be calculated in R and found that the "igraph" package has the option
of "similarity.dice" to do this. But, for this command, the input object
should be an igraph object. But, I have a dataframe of columns
containing 1's and 0's. Can I convert this dataframe into an igraph
object, so that