Displaying 20 results from an estimated 1000 matches similar to: "slowness when I use a list comprehension"
2024 Jun 16
1
slowness when I use a list comprehension
This can be vectorized. Try
ix <- seq_along(vec2)
S_diff2 <- sapply(seq_len(N1-(N2-1)*ratio_sampling), \(j)
sum((vec1[(ix-1)*ratio_sampling+j] - vec2[ix])**2))
On Sun, Jun 16, 2024 at 11:27?AM Laurent Rhelp <laurentRHelp at free.fr> wrote:
>
> Dear RHelp-list,
>
> I try to use the package comprehenr to replace a for loop by a list
> comprehension.
>
> I
2024 Jun 16
1
slowness when I use a list comprehension
I would be more strong on this advice: learn to think in R, rather than thinking in Python, when programming in R. R has atomic vectors... Python does not (until you import a package that implements them). I find that while it is possible to import R thinking into Python, Python programmers seem to object for stylistic reasons even though such thinking speeds up Python also.
A key step in that
2024 Jun 16
1
slowness when I use a list comprehension
Laurent,
Thank you for introducing me to a package I did not know existed as I use features like list comprehension in python all the time and could see using it in R now that I know it is available.
As to why you see your example as slow, I see you used a fairly complex and nested expression and wonder if it was a better way to go. As you are dealing with an interpreter doing delayed
2024 Jun 16
1
slowness when I use a list comprehension
I fully agree with Jeff that the best way to use ANY language is to evaluate
the language in terms of not just the capabilities it offers but also the
philosophy behind what it was created for and how people do things and just
grok it and use it mostly in the way intended. I do that with all the
languages I learn, whether for computers or humans.
Bringing in something you like from another
2009 Jul 27
1
how to use do.call together with cbind and get inside a function
Dear R-helpers:
I have a question related to using do.call to call cbind and get.
#the following works
vec1 <- c(1,2)
vec2 <- c(3,4)
ColNameVec <- c('vec1','vec2')
mat <- do.call("cbind",lapply(ColNameVec,get))
mat
#put code above into a function then it does not work
#before doing so, first remove vec1 and vec2 from global environment
rm(vec1,vec2)
test
2008 Dec 30
2
[LLVMdev] Folding vector instructions
Hello.
Sorry I am not sure this question should go to llvm or mesa3d-dev mailing
list, so I post it to both.
I am writing a llvm backend for a modern graphics processor which has a ISA
very similar to that of Direct 3D.
I am reading the code in Gallium-3D driver in a mesa3d branch, which
converts the shader programs (TGSI tokens) to LLVM IR.
For the shader instruction also found in LLVM IR,
2008 May 12
1
lexicographic comparison of two vectors
Is there any built-in way to lexicographically compare two vectors of
the same length in R? The textbook algorithm could be coded as follows:
lex.cmp <- function (vec1,vec2) {
for (j in 1:length(vec1)) {
if (vec1[j] < vec2[j]) { return(-1) }
if (vec1[j] > vec2[j]) { return(1) }
}
return(0)
}
Thanks,
Gabriel
2010 Jul 12
2
findInterval and data resolution
Hello Wise Ones...
I need a clever way around a problem with findInterval. Consider:
vec1 <- 1:10
vec2 <- seq(1, 10, by = 0.1)
x1 <- c(2:3)
a1 <- findInterval(x1, vec1); a1 # example 1
a2 <- findInterval(x1, vec2); a2 # example 2
In the problem I'm working on, vec* may be either integer or numeric, like
vec1 and vec2. I need to remove one or more sections of this vector;
2004 Jul 09
3
Problem with bwplot
Try factor(vec2) in your bwplot() call.
-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Ernesto Jardim
Sent: Friday, July 09, 2004 9:41 AM
To: Mailing List R
Subject: [R] Problem with bwplot
Hi,
I'm ploting some box-and-whisker plots with bwplot but I'm not getting
any box-and-whiskers ... just dots.
2010 Aug 24
3
multiple assignments ?
Simple one, have read and googled, still no luck!
I want to create several empty vectors all of the same length.
I would like multiple empty vectors (vec1, vec2, vec3) and want to create them all in one line.
I've tried
vec1,vec2,vec3 <- vector(length=5)
and
c(vec1,vec2,vec3) <- vector(length=5)
and several other attempts but nothing seems to work ... suggestions?
Thanks
Jim
2011 Jun 03
2
Arules: R Crashes when running eclat with tidLists=TRUE
Hello,
I'm using the eclat function of the arules package (1.0-6) for the
identification of frequent itemsets. I need the tidLists, but if I set
in the function tidLists=TRUE R crashes (Windows XP Professional SP3,
32 bit, R version 2.12.1 (2010-12-16), reproducible on two different
computers) with two different error messages or non at all. Minimum
examples are:
library(arules)
2013 Mar 22
2
A question on function return
Hello again,
Let say I have following user defined function:
fn <- function(x, y) {
Vec1 <- letters[1:6]
Vec2 <- 1:5
return(list(ifelse(x > 0, Vec1, NA), ifelse(y > 0, Vec2, NA)))
}
Now I have following calculation:
> fn(-3, -3)
[[1]]
[1] NA
[[2]]
[1] NA
> fn(3, -3)
[[1]]
[1] "a"
[[2]]
[1] NA
Here I can not understand why in the second case, I get
2008 Sep 20
1
lower and upper limits in integrate as vectors
Dear R useRs,
i try to integrate the following function for many values
"integrand" <- function(z)
{
return(z * z)
}
i do this with a for-loop
for(i in 2:4)
{
z <- integrate(integrand, i-1, i)$value
cat("z", z, "\n")
}
to speed up the computation for many values i tried vectors
in integrate to do this.
vec1<-1:3
vec2<-2:4
2013 Apr 18
1
vectors with equal values
Hi,
Try:
?vec1<-c(1,1,1,1,1,1,1,1,1)
if(all(vec1==1)) "xxxxxxxxx" else? "yyyyyyyyyyy"
#[1] "xxxxxxxxx"
?vec2<-c(rep(1,4),2)
?if(all(vec2==1)) "xxxxxxxxx" else? "yyyyyyyyyyy"
#[1] "yyyyyyyyyyy"
#or
if(length(unique(vec1))==1) "xxxxxxxxx" else? "yyyyyyyyyyy"
#[1] "xxxxxxxxx"
? if(length(unique(vec2))==1)
2001 Nov 01
1
Erratic behaviour of sammon()
I'm not sure this list is the right place for this thing.
I noticed some erratic behaviour in sammon(). Running sammon on
two nearly identical sets of data results in very different
results. Below is an example. I create an initial configuration
with cmdscale() and store it into 'vec1'. I write this to file,
and read it back in again to 'vec2'. According to cor() on the
three
2011 Apr 14
1
nesting multiple for loops
Hi everyone.
I am quite frustrated that this doesn't work, as all the functions within
work fine by themselves. I'd also like any pointers to how to avoid 'for'
loops in my code. I understand it's less than desirable, but I'm still quite
new and use them a lot.
I have a few wide datasets (90 to 120) with long column names, each name
contains a number of different
2012 May 04
1
Equality of multiple vectors
Hello,
I'm writing a piece of code where I need to compare multiple same length
vectors.
I've gone through the basic functions like identical() or all(), but they
only work for comparing 2 vectors. From 3 vectors on, it doesn't work .
Example: Assuming
vec1 <- c (1,2,3,4,5)
vec2 <- c(1,2,3,4,5)
vec3 <- c(1,2,3,4,4)
identical (vec1,vec2,vec3) returns TRUE, since the 2
2011 Apr 01
1
How to paste a vector of expressions and a character vector?
Dear expeRts,
I know I can't paste expressions in the normal way, but I just couldn't figure out
how to get the following (I want to paste a character vector to an expression vector)
right with bquote() or substitute.
vec1 <- c("a", expression(tilde(b)), "c")
vec2 <- c("1", "2", "3")
main <- as.expression(paste(vec1, vec2))
2007 Feb 01
2
Losing factor levels when moving variables from one context to another
Hi, there
I'm currently trying to figure out how to keep my "factor" levels for a
variable when moving it from one data frame or matrix to another.
Example below:
vec1<-(rep("10",5))
vec2<-(rep("30",5))
vec3<-(rep("80",5))
vecs<-c(vec1, vec2, vec3)
resp<-rnorm(2,15)
dat<-as.data.frame(cbind(resp, vecs))
2013 Jun 18
1
transform 3 numeric vectors empty of 0/1
Dear all,
Without a loop, I would like transform 3 numeric vectors empty of 0/1 of
same length
Vec1 : transform 1 to A and 0 to ""
Vec2 : transform 1 to B and 0 to ""
Vec3 : transform 1 to C and 0 to ""
to obtain only 1 vector Vec who is the paste of the 3 vectors (Ex : ABC,
BC, AC, AB,...)
Any idea ?
Thank you for your help
--
Michel ARNAUD