Displaying 20 results from an estimated 2000 matches similar to: "an apply question"
2012 Nov 27
3
loop command to matrix
Dear UseRs,Extremely sorry for a basic question. I have a matrix of 19 rows and 365 columns. what i want to do is the following...First i want to leave out column number 1 and want to calculate the row wise mean of the remaining columns, which will obviously give me 365 values in one column, and then subtracting these values from the column i left out i.e. col=1 then i want to leave out column 2
2012 Dec 05
3
data manipulation between vector and matrix
Dear list,
I was curious how to subtract a vector from matrix?
Say, I have
mat <- matrix(1:40, nrow=20, ncol=2)
x <-c(1,2)
I want,
x-mat[1,] and x-mat[2,], and so on... Basically, subtract column elements
of x against column elements in mat.
But x-mat won't do it.
Thanks,
Mike
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2007 Feb 02
1
Assigning labels to a list created with apply
I have a simple data base and I want to produce tables
for each variable. I wrote a simple function
fn1 <- function(x) {table(x)} where x is a matrix or
data.frame. and used apply to produce a list of
tables. Example below.
How do I apply the colnames from the matrix or names
from the data.frame to label the tables in the results
in the list. I know that I can do this individually
but
2007 May 22
2
R-help with apply and ccf
Dear R gurus,
I would like to use the ccf function on two matrices that are each 196000 x
12. Ideally, I want to be able to go row by row for the two matrices using
apply for the ccf function and get one 196000 X 1 array output. The apply
function though wants only one array, no? Basically, is there a way to use
apply when there are two arrays in order to do something like correlation on
a row
2005 Jul 13
5
maps drawing
Hello,
is there a package in R that would allow map drawing:
coastlines, country/state boundaries, maybe
topography,
rivers etc?
Thanks for any guidance,
Mark
2013 Sep 02
3
Product of certain rows in a matrix
Hi,
You could try:
A<- matrix(unlist(read.table(text="
1 2 3
4 5 6
7 8 9
9 8 7
6 5 4
3 2 1
",sep="",header=FALSE)),ncol=3,byrow=FALSE,dimnames=NULL)
library(matrixStats)
?res1<-t(sapply(split(as.data.frame(A),as.numeric(gl(nrow(A),2,6))),colProds))
?res1
#? [,1] [,2] [,3]
#1??? 4?? 10?? 18
#2?? 63?? 64?? 63
#3?? 18?? 10??? 4
2010 Feb 12
3
Code working but too slow, any idea for how to speed it up ?(no loop in it)
Hello my friends,
here is a code I wrote with no loops on matrix that is taking too long (2
seconds and I call him 720 times --> 12 minutes):
mat1 and mat2 are both matrix with 103 columns and 164 rows.
sequence <- matrix(seq(1 : ncol(mat1)))
returns <- apply(sequence, 1, function, mat1= mat1, mat2 = mat2, day = 1)
function<- function(mat1, mat2, colNb, day){
2005 Nov 03
4
merging dataframes
Dear List,
I often have to merge two or more data frames containing unique row
names but with some columns (names) common to the two data frames and
some columns not common. This toy example will explain the kind of setup
I am talking about:
mat1 <- as.data.frame(matrix(rnorm(20), nrow = 5))
mat2 <- as.data.frame(matrix(rnorm(20), nrow = 4))
rownames(mat1) <- paste("site",
2010 Jan 29
7
Simple question on replace a matrix row
Hello, I have a matrix mat1 of dim [1,8] and mat2 of dim[30,8], I want to
replace the first row of mat2 with mat1, this is what I do:
mat2[1,]<-mat1 but it transforms mat2 in a list I don't understand, I want
it to stay a matrix...
-----
Anna Lippel
--
View this message in context: http://n4.nabble.com/Simple-question-on-replace-a-matrix-row-tp1427857p1427857.html
Sent from the R help
2007 Nov 12
1
update matrix with subset of it where only row names match
I guess this has a simple solution:
I have matrix 'mat1' which has row and column names, e.g.:
A B C
row1 0 0 0
row2 0 0 0
....
rown 0 0 0
I have a another matrix 'mat2', essentially a subset of 'mat1' where the
rownames are all in 'mat1' e.g.:
B
row3 5
row8 6
row54 7
I want to insert the values of matrix mat2 for column B (in reality it
could be some or
2009 Apr 16
2
error bars in matplot
Hi,
I was trying to get error bars in my matplot. I looked at an earlier thread, and the sample code that I made is:
#------------------
library(plotrix)
mat1 <- matrix(sample(1:30,10),nrow=5,ncol=2)
ses <- matrix(sample(1:3,10,replace=T),nrow=5,ncol=2)
vect <- seq(20,100,20)
rownames(mat1) <- rownames(ses) <- vect
colnames(mat1) <- colnames(ses) <- letters[1:2]
2005 Oct 06
1
Compare two distance matrices
Hi all,
I am trying to compare two distance matrices with R. I would like to
create a XY plot of these matrices and do some linear regression on
it. But, I am a bit new to R, so i have a few questions (I searched in
the documentation with no success).
The first problem is loading a distance matrix into R. This matrix is
the output of a the Phylip program Protdist and lookes like this:
5
2013 Sep 20
3
search species with all absence in a presence-absence matrix
Dear list
I have a matrix composed of islandID as rows and speciesID as columns.
IslandID: Island A, B, C….O (15 islands in total)
SpeciesID: D0001, D0002, D0003….D0100 (100 species in total)
The cell of the matrix describes presence (1) or absence (0) of the species
in an island.
Now I would like to search the species with absence (0)
in all the islands (Island A to Island O.)
2013 Sep 26
1
Grouping Matrix by Columns; OHLC Data
HI,
May be this helps:
set.seed(24)
?mat1<- matrix(sample(1:60,30*24,replace=TRUE),ncol=24)
colnames(mat1)<- rep(c("O","H","L","C"),6)
indx<-seq_along(colnames(mat1))
n<- length(unique(colnames(mat1)))
?res<- lapply(split(indx,(indx-1)%%n+1),function(i) mat1[,i])
lapply(res,head,2)
#$`1`
#????? O? O? O? O? O? O
#[1,] 18 56 51 24 24 52
#[2,]
2007 Nov 21
2
matrix elementwise average with NA's
Hello fellow R users,
I have a matrix computation that I imagine should be relatively easy to do, however I cannot figure out a nice way to do it. I have two matrices, for example
mat1 <- matrix(c(1:5,rep(NA,5), 6:10), nrow=3, byrow=T)
mat2 <- matrix(c(2:6, 6:10, rep(NA,5)), nrow=3, byrow=T)
I'd like to compute the element-wise average for non-NA entries. Of course
(mat1+mat2)/2
2003 Oct 31
2
Summing elements in a list
Hi,
Suppose that I have a list where each component is a list of two
matrices. I also have a vector of weights. How can I collapse my
list of lists into a single list of two matrices where each matrix
in the result is the weighted sum of the corresponding matrices.
I could use a loop but this is a nested calculation so I was hoping
there is a more efficient way to do this. To help clarify,
2013 Apr 15
3
Indices of lowest values in matrix
Dear R users,Sorry for such a basic question. I really need to know that how can i pick the indices of 5 lowest values from each row of a matrix with dimensions 12*12??Thank you very much in advance
Elisa
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2013 Sep 27
3
Compare species presence and absence between sites
Dear List,
I want to compare the presence and absence of bird species based on the
sites in a matrix.
The matrix has 5 rows for Island A, B, C, D, and E.
It has 100 columns for bird species D001-D100.
In each cell of the matrix,
the presence-absence of bird species will be recorded as 1 or 0.
(For example, if species D001 is found on Island D,
the matrix cell of species D001 and Island D
2010 Jan 27
1
How to sort data.frame
Dear R heleprs
Suppose I have following data
Scenarios
combination_names
series1
series2
Sc1
MAT2 GAU1
7.26554
8.409778
Sc2
MAT2 GAU2
7.438128
8.130275
Sc3
MAT3 GAU1
8.058422
8.06457
Sc4
MAT1 GAU2
8.179855
8.022071
Sc5
MAT3 GAU2
8.184033
8.191831
Sc6
MAT3 GAU2
7.50312
8.232425
Sc7
MAT1 GAU2
7.603291
8.200993
Sc8
MAT1 GAU1
8.221755
8.380097
Sc9
MAT3 GAU2
7.904908
2003 Mar 20
2
Matrix problems
Hi all.
I do not know if it is a bug in the windows version but i have this
problem.
Reading a file with 200000 rows, 2 columns and transforming into a
200000 x 2 matrix.
If I try to find an element by using the which command which gives
some correct indexes plus some others passing the 200000 row
boundaries.
If I try to reach those "outbound" indexs I get an "Error: subscript out