Displaying 20 results from an estimated 10000 matches similar to: "merge character strings"
2011 Oct 13
3
Create order of numbers based on a given vector
Hello!
If I have a vector vec <- c(FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, FALSE
FALSE)
I can I create the following order of numbers based on vector vec:
1, 2, 2, 3, 3, 3, 4, 5
Whenever there is a FALSE I increase the number (starting with 1).
Whenever there is a TRUE I set the same number as the previous FALSE has
been assigned to.
I would be happy for any input
Cheers,
Syrvn
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2012 Feb 12
3
Vector manipulation
Hello,
I am stuck with the following problem. Consider the vector:
vec <- c(2,4,6,9,10)
I now want to use R to manipulate the vector as follows:
[1] 2, 4, 2, 6, 2, 9, 2, 10
In words, the first element of the vector should be placed in front of each
following number.
Which R commands do I need to achieve that?
Cheers
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2009 Nov 25
3
Random data
Hi,
how can I produce random data which lies around a straight line with angle
45 degree.
Similar to this image: http://zoonek2.free.fr/UNIX/48_R/g134.png
Cheers
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2010 Aug 17
4
replacing values in a vector
Dear helpRs
Does anyone have an elegant way of doing the following:
For a given numeric vector, e.g. vec <- c(3,2,6,4,7)
Create a series of vectors where all but 1 of the values are replaced by
0's, e.g.
vec.a <- c(3,0,0,0,0)
vec.b <- c(0,2,0,0,0)
vec.c <- c(0,0,6,0,0)
vec.d <- c(0,0,0,4,0)
vec.e <- c(0,0,0,0,7)
I have looked at `replace', but can't think of a
2009 Nov 09
6
Find the first values in vector
Hi !
I have a vector:
vec= TRUE TRUE TRUE TRUE FALSE FALSE FALSE FALSE TRUE TRUE FALSE
and I'm looking for a method which let me get only the first values equal
TRUE from this vector. It means that I want to get a vector:
vec_out = TRUE TRUE TRUE TRUE
or posictions values = TRUE: vec_out = 1,2,3,4
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2011 Oct 06
3
Duplicate elements of a vector
Hi,
let's assume I have the following vector a:
1 5 23
How can I use R to duplicate the elements so that my new vector looks like:
1 1 5 5 23 23
Many thanks,
Syrvn
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2010 Nov 09
3
Row-wise recurive function call
Dear Group,
I have a following dataset:
> a
A B C D
1 22 3 31 40
2 26 31 36 32
3 3 7 49 16
4 24 40 27 26
5 20 45 47 0
6 34 43 11 18
7 48 48 24 2
8 3 16 39 48
9 20 49 7 21
10 17 36 47 10
> dput(a)
structure(list(A = c(22L, 26L, 3L, 24L, 20L, 34L, 48L, 3L, 20L,
17L), B = c(3L, 31L, 7L, 40L, 45L, 43L, 48L, 16L, 49L, 36L),
C = c(31L, 36L, 49L, 27L, 47L, 11L, 24L,
2012 Apr 20
3
Matrix multiplication by multple constants
Dear R helpers
Suppose
x <- c(1:3)
y <- matrix(1:12, ncol = 3, nrow = 4)
> y
[,1] [,2] [,3]
[1,] 1 5 9
[2,] 2 6 10
[3,] 3 7 11
[4,] 4 8 12
I wish to multiply 1st column of y by first element of x i.e. 1, 2nd column of y by 2nd element of x i.e. 2 an so on. Thus the resultant matrix should be like
> z
[,1] [,2] [,3]
[1,] 1
2010 Mar 11
2
divid the rows of the matrix by the cector
Hi,
I have a matrix with m rows and n column and a vector with n elements. I
want to divid each rows of the matrix by vector direcly.
could you please hint me?
Thank you
khazaei
2009 Feb 17
2
Efficient matrix computations
Hi,
I am looking for two ways to speed up my computations:
1. Is there a function that efficiently computes the 'sandwich product' of
three matrices, say, ZPZ'
2. Is there a function that efficiently computes the determinant of a
positive definite symmetric matrix?
Thanks,
S.A.
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2008 Sep 17
5
Loop on vector name
[My previous message rejected, therefore I am sending same one with some modification]
I have 3 vectors with object name : dat1, dat2, dat3
Now I want to create a loop, like :
for (i in 1:3)
{
cat(sd(dati))
}
How I can do this in R?
Regards,
2008 Dec 11
5
Extracting the name of an object into a character string
Dear List,
I am writing a function in R with the facility to store models for later
use in scoring.
It would be very useful if I could include in the name of the file
stored the name of
the model object being stored, this name being chosen by the user in the
function
call. A simple function to store the name of an object as a character
string would fit the
bill, but I have not found one. name()
2010 Jul 26
2
Concatenate a mix of numbers and letters to create a vector name
Dear all,
I am trying to create a vector name, for example tmax.195012 from tmax., 1950 and 12. Obviously I don't wish to simply type it because the 3 name components are changing in each iteration within a loop. Is there any way of concatenating those 3 components (which are a mixture of numbers and letters)?
Thanks for reading,
Panos
2011 Aug 23
4
Correlation discrepancy
Dear R list, I have one very elementary question regrading correlation between two variables.
x = c(44,46,46,47,45,43,45,44)
y = c(44,43,41,41,46,48,44,43)
> cov(x, y)
[1] -2.428571
However, if I try to calculate the covariance using the formula as
covariance = sum((x-mean(x))*(y-mean(y)))/8 # no of of paired obs. = 8
or
covariance = sum(x*y)/8-(mean(x)*mean(y))
gives
2010 Mar 09
3
Removing Zeros from matrix
Hi Everybody,
I have a matrix of about 45 columns. Some of the rows contain zeros. Using
>data1<-data[complete.cases(data),], I can remove the "NA" rows. But I am
unable to tackle that of zeros.
Can anybody give me an idea of how to remove rows containing zeros in a
matrix.
Thanks so much
Best
Ogbos
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2008 Oct 14
4
request: How to ignore columns having zero sums
Dear friends
I have an array consist of r-rows and c-columns e.g.
x=c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,0,0,0,0,0,0,0,0);
x1=array(x, dim=c(4,6))
output is
> x1
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 2 3 4 0 0
[2,] 1 2 3 4 0 0
[3,] 1 2 3 4 0 0
[4,] 1 2 3 4 0 0
How can i ignore columns having zero sums? Help in this regard
2010 Sep 06
3
Aggregate certain rows in a matrix
Hi,
I have a matrix that looks like this
a <- c(1,1,1,1,2,2,3,3,3,3)
b <- c(2,2,2,3,4,4,4,5,5,6)
c <- c(1,2,3,4,5,6,7,8,9,10)
M <- matrix(nr=10,nc=3)
M[,1] <- a
M[,2] <- b
M[,3] <- c
> M
[,1] [,2] [,3]
[1,] 1 2 1
[2,] 1 2 2
[3,] 1 2 3
[4,] 1 3 4
[5,] 2 4 5
[6,] 2 4 6
[7,] 3 4 7
2009 Jun 08
5
mean
Hi,
I have gote the following data
x1 <- c(rep(1,6),rep(4,7),rep(6,10))
x2 <- rnorm(length(x1),6,1)
data <- data.frame(x1,x2)
and I would like to compute the mean of the x2 for each individual of x1, i. e. x1=1,4 and 6?
Thank you very much in advance,
Amori
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2012 Nov 01
3
convert list without same component length to matrix
Hi,
I have this lame question. I want to convert a list (each with varies in
length) to matrix with same row length by eliminating vectors outside the
needed range.
For example:
l<-list(NULL)
l[[1]]=1,2,3.7
l[[2]]=3,4,5,6,3
l[[3]]=4,2,5,7
l[[4]]=2,4,6,3,2
l[[5]]=3,5,7,2
#so say I want to only have 4 rows and 5 column in my matrix (or
data.frame) and eliminating the 5th index value in l[[2]]
2011 Sep 19
2
pasting elements of one character vector together
hello,
i am familiar with the paste command with which i can paste for exaple:
object <- "Hello"
paste(object,"World")
now i would like to be able to paste all the elements of the same vector
together e.g:
object <- c("Hello","World")
getting as a result also:
"Hello World".
Does anyone know the solution to this problem?
Thank you