Displaying 20 results from an estimated 6000 matches similar to: "extract index during execution of sapply"
2006 Jan 20
2
assign object to list
Dear all
I want to generate a list like this:
a <- data.frame(1:10)
attr(a,'myattribute') <- 'something'
b <- data.frame(11:20)
attr(b,'myattribute') <- 'anything'
mylist <- list(a,b)
Is there a way to place the dataframes into the list giving them the
attribute at the same time?
I don't want to create all the dataframes in my workspace first.
2007 Jun 24
2
matlab/gauss code in R
Hi all!
I would like to import a matlab or gauss code to R.
Could you help me?
Bye,
Sebasti?n.
2007/6/23, r-help-request en stat.math.ethz.ch <r-help-request en stat.math.ethz.ch>:
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2005 Nov 29
1
Indexing variables within lapply?
Hello
I am using R 2.2.0 with Windows XP.
I've got a five element list object, each element containing two
dataframes of equivalent size.
> str(mylist)
List of 1
$ data1:List of 2
..$ data1a :`data.frame': 77 obs. of 63 variables:
.. ..$ var1 : num [1:77] 0.41375 0.00056 1.43040 1.43528 0.61730 ...
.. ..$ var2 : num [1:77] 1.154 1.686 0.673 0.800 0.760 ...
..
2006 Feb 14
2
How to handle large dataframes?
Dear all
I imported a Stata .dta file with the read.dta-function from the
foreign-package. The dataframe's dimensions are
> dim(d.apc)
[1] 15806 1300
Importing needs up to 15 min and calculations with these data are rather
slow (although I subset the data before starting analyses).
My questions are:
1. Has someone experiences importing Stata files (alternatives to
read.dta) ?
2.
2018 Mar 13
0
Possible Improvement to sapply
Wouldn't that change how simplify='array' is handled?
> str(sapply(1:3, function(x)diag(x,5,2), simplify="array"))
int [1:5, 1:2, 1:3] 1 0 0 0 0 0 1 0 0 0 ...
> str(sapply(1:3, function(x)diag(x,5,2), simplify=TRUE))
int [1:10, 1:3] 1 0 0 0 0 0 1 0 0 0 ...
> str(sapply(1:3, function(x)diag(x,5,2), simplify=FALSE))
List of 3
$ : int [1:5, 1:2] 1 0 0 0 0 0 1 0 0
2011 Jan 15
3
get list element names within lapply / sapply call
Hi all,
I would like to iterate through a list with named elements and access the
names within an lapply / sapply call. One way to do this is iterate through
the names and index the list with the name. Is there a way to iterate
through the list elements themselves and access the element names within in
the function? For example,
mylist <-
2018 Mar 13
1
Possible Improvement to sapply
You?re right, it sure does. My suggestion causes it to fail when simplify = ?array?
From: William Dunlap [mailto:wdunlap at tibco.com]
Sent: Tuesday, March 13, 2018 12:11 PM
To: Doran, Harold <HDoran at air.org>
Cc: r-help at r-project.org
Subject: Re: [R] Possible Improvement to sapply
Wouldn't that change how simplify='array' is handled?
> str(sapply(1:3,
2018 Mar 13
0
Possible Improvement to sapply
On 03/13/2018 09:23 AM, Doran, Harold wrote:
> While working with sapply, the documentation states that the simplify argument will yield a vector, matrix etc "when possible". I was curious how the code actually defined "as possible" and see this within the function
>
> if (!identical(simplify, FALSE) && length(answer))
>
> This seems superfluous to me,
2018 Mar 13
4
Possible Improvement to sapply
While working with sapply, the documentation states that the simplify argument will yield a vector, matrix etc "when possible". I was curious how the code actually defined "as possible" and see this within the function
if (!identical(simplify, FALSE) && length(answer))
This seems superfluous to me, in particular this part:
!identical(simplify, FALSE)
The preceding
2018 Mar 13
2
Possible Improvement to sapply
Martin
In terms of context of the actual problem, sapply is called millions of times because the work involves scoring individual students who took a test. A score for student A is generated and then student B and such and there are millions of students. The psychometric process of scoring students is complex and our code makes use of sapply many times for each student.
The toy example used
2018 Mar 13
1
Possible Improvement to sapply
Could your code use vapply instead of sapply? vapply forces you to declare
the type and dimensions
of FUN's output and stops if any call to FUN does not match the
declaration. It can use much less
memory and time than sapply because it fills in the output array as it goes
instead of calling lapply()
and seeing how it could be simplified.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Tue,
2018 Mar 13
0
Possible Improvement to sapply
Quite possibly, and I?ll look into that. Aside from the work I was doing, however, I wonder if there is a way such that sapply could avoid the overhead of having to call the identical function to determine the conditional path.
From: William Dunlap [mailto:wdunlap at tibco.com]
Sent: Tuesday, March 13, 2018 12:14 PM
To: Doran, Harold <HDoran at air.org>
Cc: Martin Morgan <martin.morgan
2006 Jun 30
2
Passing arguments to glm()
Hi there
I want to pass arguments (i.e. the response variable and the subset
argument) in a self-made function to glm.
Here is one way I can do this:
f.myglm <- function(y,subfact,subval) {
glm(d.mydata[,y]~d.mydata[,'x1'],family=binomial,subset=d.mydata[,subfact]==subval)
}
> str(d.mydata)
`data.frame': 15806 obs. of 3 variables:
$ y : Factor w/ 2 levels
2011 Apr 05
1
Help in splitting a list
Dear R users,
Let's say I have a list with components being 'm' matrices (as exemplified
in the "mylist" object below). Now, I'd like to subset this list based on an
index vector, which will partition each matrix 'm' in 2 sub-matrices. My
questions are:
1. Is there an elegant way to have the results shown in mylist2 for an
arbitrary number of matrices in mylist?
2004 May 10
2
Lists and outer() like functionality?
Hi,
I'm have a list of integer vectors and I want to perform an outer()
like operation on the list. As an example, take the following list:
mylist <- list(1:5,3:9,8:12)
A simple example of the kind of thing I want to do is to find the sum
of the shared numbers between each vector to give a result like:
result <- array(c(15,12,0,12,42,17,0,17,50), dim=c(3,3))
Two for() loops is the
2011 May 25
3
Accessing elements of a list
I have a list that is made of lists of varying length. I wish to create a
new vector that contains the last element of each list. So far I have used
sapply to determine the length of each list, but I'm stymied at the part
where I index the list to make a new vector containing only the last item
of each list
mylist =
2006 Feb 17
1
extracting a element with a name attribute from a list
Hi R users
I like to extract (or collect) a numeric element with a name from a list.
Is there any way to extract just a numeric element without the name attached
to the element.
For example,
>mylist
Mantel-Haenszel chi-squared test with continuity correction
data: table(mydata[, x])
Mantel-Haenszel X-squared = 8.3832, df = 1, p-value = 0.003787
alternative hypothesis: true
2015 May 04
2
Define replacement functions
Hello
I tried to define replacement functions for the class "mylist". When I test them in an active R session, they work -- however, when I put them into a package, they don't. Why and how to fix?
make_my_list <- function( x, y ) {
return(structure(list(x, y, class="mylist")))
}
mylist <- make_my_list(1:4, letters[3:7])
mylist
mylist[['x']] <- 4:6
2013 Feb 12
3
grabbing from elements of a list without a loop
Hello!
# I have a list with several data frames:
mylist<-list(data.frame(a=1:2,b=2:3),
data.frame(a=3:4,b=5:6),data.frame(a=7:8,b=9:10))
(mylist)
# I want to grab only one specific column from each list element
neededcolumns<-c(1,2,0) # number of the column I need from each element of
the list
# Below, I am doing it using a loop:
newlist<-NULL
for(i in 1:length(mylist) ) {
2009 Oct 25
3
NULL elements in lists ... a nightmare
I can define a list containing NULL elements:
> myList <- list("aaa",NULL,TRUE)
> names(myList) <- c("first","second","third")
> myList
$first
[1] "aaa"
$second
NULL
$third
[1] TRUE
> length(myList)
[1] 3
However, if I assign NULL to any of the list element then such
element is deleted from the list:
> myList$second <-