Displaying 20 results from an estimated 30000 matches similar to: "Length of vector without NA's"
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]]
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,
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
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 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 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.
[[alternative HTML version deleted]]
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 Aug 04
4
Adding collumn to existing data frame
Hi experts,
I am trying to write a very flexible method that allows me to add a
new column to an existing data frame. This is what I have so far:
add.column <- function(df, new.col, name) {
n.row <- dim(df)[1]
length(new.col) <- n.row
names(new.col) <- name
return(cbind(df, new.col))
}
df <- NULL
df <- data.frame(a=c(1,2,3))
df
# corect: added NA to new collumn
df <-
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
[[alternative HTML version deleted]]
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
2009 Jul 13
4
Combine two matricies
Hi,
I have two matricies a and x:
a<-matrix(c(3,4,5,2,3,4,1,1,2), nrow=3, ncol=3)
[,1] [,2] [,3]
[1,] 3 2 1
[2,] 4 3 1
[3,] 5 4 2
x<-matrix(c(3, NA, NA, NA, 2, 5, NA, 2, 2), nrow=3, ncol=3)
[,1] [,2] [,3]
[1,] 3 NA NA
[2,] NA 2 2
[3,] NA 5 2
I wish to combine these two into one matrix using the values from x where x has values, and
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
[[alternative HTML version deleted]]
2011 Nov 02
1
Generate a sequence of vectors of different length
Hi everyone
After the following setup
sector=2 # Define Number of Sectors
sectors=LETTERS[seq( from = 1, to = sector )] # Name sectors
No_ent=round(3/runif(sector)) # Number of entities per sector
#Tot_No_ent=sum(No_ent)
Goal is to get a List like
(A1, A2, A3, B1, B2, B3, B4) where A is denoting an industrial sector and
then a numbered sequence of companies within the sector.
The step
2010 Nov 25
1
Applying function to elements of matrices in a list
Hello R-help,
Please cc me on all responses, as I only receive summary emails from
this list.
I'm wondering if anybody has any tips on how to accomplish this
efficiently. I have a list of matrices, and I'm trying to get the mean
of the [i,j]'th element of each matrix in a list.
So if I have a list of matrices, say
x <-
2009 Nov 05
2
sort of cumulative counting in a vector
Dear list,
I need help, since I can not come up with an easy solution to convert
this vector
test <- c('p','p','t','t','t')
to
[1] NA NA 1 2 3
which means the occurences of 't' should be summed up at the
corresponding positions. The solution should also be able to handle the
following scenarios:
test2 <-
2009 Mar 07
2
Recode factor into binary factor-level vars
How to I "recode" a factor into a binary data frame according to the
factor levels:
### example:start
set.seed(20)
l <- sample(rep.int(c("locA", "locB", "locC", "locD"), 100), 10,
replace=T)
# [1] "locD" "locD" "locD" "locD" "locB" "locA" "locA" "locA"
2009 Nov 21
7
consecutive numbering of elements in a matrix
Within a very large matrix composed of a mix of values and NAs, e.g, matrix A:
[,1] [,2] [,3]
[1,] 1 NA NA
[2,] 3 NA NA
[3,] 3 10 17
[4,] 4 12 18
[5,] 6 16 19
[6,] 6 22 20
[7,] 5 11 NA
I need to be able to consecutively number, in new columns, the non-NA
values within each column (i.e. A[1,1] A[3,2] and A[3,3] would all be set
to one, and
2010 Feb 15
2
creating functions question
Hi All,
I am interested in creating a function that will take x number of lm
objects and automate the comparison of each model (using anova). Here
is a simple example (the actual function will involve more than what
Im presenting but is irrelevant for the example):
# sample data:
id<-rep(1:20)
n<-c(10,20,13,22,28,12,12,36,19,12,36,75,33,121,37,14,40,16,14,20)