similar to: Array reversed

Displaying 20 results from an estimated 50000 matches similar to: "Array reversed"

2017 Jun 01
3
Reversing one dimension of an array, in a generalized case
Here is an alternative approach using apply(). Note that with apply() you are reversing rows or columns not indices of rows or columns so apply(junk, 2, rev) reverses the values in each column not the column indices. We actually need to use rev() on everything but the index we are interested in reversing: f2 <- function(a, wh) { dims <- seq_len(length(dim(a))) dims <-
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
?? > z <- array(1:24,dim=2:4) > all.equal(f(z,3),f2(z,3)) [1] "Attributes: < Component ?dim?: Mean relative difference: 0.4444444 >" [2] "Mean relative difference: 0.6109091" In fact, > dim(f(z,3)) [1] 2 3 4 > dim(f2(z,3)) [1] 3 4 2 Have I made some sort of stupid error here? Or have I misunderstood what was wanted? Cheers, Bert Bert Gunter
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
How about this: f <- function(a,wh){ ## a is the array; wh is the index to be reversed l<- lapply(dim(a),seq_len) l[[wh]]<- rev(l[[wh]]) do.call(`[`,c(list(a),l)) } ## test z <- array(1:120,dim=2:5) ## I omit the printouts f(z,2) f(z,3) Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into
2017 Jun 01
5
Reversing one dimension of an array, in a generalized case
Hi All: I have been looking for an elegant way to do the following, but haven't found it, I have never had a good understanding of any of the "apply" functions. A simplified idea is I have an array, say: junk(5, 10, 3) where (5, 10, 3) give the dimension sizes, and I want to reverse the second dimension, so I could do: junk1 <- junk[, rev(seq_len(10), ] but what I am
2017 Jun 01
2
Reversing one dimension of an array, in a generalized case
My error. Clearly I did not do enough testing. z <- array(1:24,dim=2:4) > all.equal(f(z,1),f2(z,1)) [1] TRUE > all.equal(f(z,2),f2(z,2)) [1] TRUE > all.equal(f(z,3),f2(z,3)) [1] "Attributes: < Component ?dim?: Mean relative difference: 0.4444444 >" [2] "Mean relative difference: 0.6109091" # Your earlier example > z <- array(1:120, dim=2:5) >
2005 Oct 07
6
Applying a function to each element of an array
Hi, I have a 7000x7000 matrix, and each element is an integer. For each element, I want to apply the function : wt <- 0 for(q in 1:count){ wt <- wt + 0.5^(q-1) } I get the value of 'count' from the elements in the matrix , and want to store the corresponding 'wt' value for that element. I suppose I could loop through the matrix, and apply the function to each
2013 Apr 05
1
Reversing data transformation
Hi everybody, I would be very grateful if you could give me your thoughts on the following issue. I need to perform Box-Cox (bcPower€) transformation on my data. To do this, I calculated lambda using the function '€powerTransform'€. powerTransform(data) However, I got an error message when performing this function: Convergence failure: return code = 52 I was told by John Fox
2013 Oct 11
3
matrix values linked to vector index
Hi, In the example you showed: m1<- matrix(0,length(vec),max(vec)) 1*!upper.tri(m1) #or ?m1[!upper.tri(m1)] <-? rep(rep(1,length(vec)),vec) #But, in a case like below, perhaps: vec1<- c(3,4,5) ?m2<- matrix(0,length(vec1),max(vec1)) ?indx <- cbind(rep(seq_along(vec1),vec1),unlist(tapply(vec1,list(vec1),FUN=seq),use.names=FALSE)) m2[indx]<- 1 ?m2 #???? [,1] [,2] [,3] [,4] [,5]
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
Thanks to all for responses/. There was a question of exactly what was wanted. It is the generalization of the obvious example I gave, >>> junk1 <- junk[, rev(seq_len(10), ] so that junk[1,1,1 ] = junk1[1,10,1] junk[1,2,1] = junk1[1,9,1] etc. The genesis of this is the program is downloading data from a variety of sources on (time, altitude, lat, lon) coordinates, but all
2012 Aug 31
3
how to find the index of points selected from a scatter plot?
Hi all, I am using "locator" to select the points from a scatter plot... This is all fine. But the problem is that the locator only returns the axis values of the selected points. Instead, I would like to get the index of these select points... The axis values are real-values so it's a bit hard for me to directly reverse-engineer the index nubmers.. How to do that? Thank you!
2017 Jun 01
3
Reversing one dimension of an array, in a generalized case
> On 1 Jun 2017, at 22:42, Roy Mendelssohn - NOAA Federal <roy.mendelssohn at noaa.gov> wrote: > > Thanks to all for responses/. There was a question of exactly what was wanted. It is the generalization of the obvious example I gave, > >>>> junk1 <- junk[, rev(seq_len(10), ] > > > so that > > junk[1,1,1 ] = junk1[1,10,1] > junk[1,2,1] =
2005 Jul 27
4
R Reference Card (especially useful for Newbies)
Newbies (and others!) may find useful the R Reference Card made available by Tom Short and Rpad at http://www.rpad.org/Rpad/Rpad-refcard.pdf or through the "Contributed" link on CRAN (where some other reference cards are also linked). It categorizes and organizes a bunch of R's basic, most used functions so that they can be easily found. For example, paste() is under the
2007 Mar 06
12
Off topic:Spam on R-help increase?
Folks: In the past 2 days I have seen a large increase of spam getting into R-help. Are others experiencing this problem? If so, has there been some change to the spam filters on the R-servers? If not, is the problem on my end? Feel free to reply privately. Thanks. Bert Gunter Genentech Nonclinical Statistics South San Francisco, CA 94404 650-467-7374
2012 Aug 20
5
Some kind of inverse of "names"
I wonder if there exists some kind of inverse of the "names" primitive in R. Let me explain what do I mean: If I create a list: -> li <- list(a=1, b=2, c=3, d=4) then I can have: -> names(li) [1] "a" "b" "c" "d" which is, I guess, some kind of vector, since -> typeof(names(li)) [1] "character" however, I haven't
2010 Jan 26
3
Apply a function on an array with the parameter as an array
Hello R buddies, I want to apply a function on an array but for each element of the array I want to use a different parameter, So here is how I tried to enter the function: apply(as.matrix(X),2, function, parameter1 = arrayOfParameter) I put X as a matrix because it was initially an element of a list. It returns me an array with the same length as X but with values that I don't even
2013 Jun 18
2
find closest value in a vector based on another vector values
Dear All, would you please provide your thoughts on the following: let us say I have: a <-c(1,5,8,15,32,69) b <-c(8.5,33) and I would like to extract from "a" the two values that are closest to the values in "b", where the length of this vectors may change but b will allways be shorter than "a". So at the end based on this example I should have the result
2013 May 13
2
reduce three columns to one with the colnames
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2017 Jun 01
1
Reversing one dimension of an array, in a generalized case
Thanks again. I am going to try the different versions. But I probably won't be able to get to it till next week. This is probably at the point where anything further should be sent to me privately. -Roy > On Jun 1, 2017, at 1:56 PM, David L Carlson <dcarlson at tamu.edu> wrote: > > On the off chance that anyone is still interested, here is the corrected function using
2012 Nov 07
9
Executing SAS Codes in R
Is there a way of executing SAS codes in R environment?   Peter Maclean Department of Economics UDSM [[alternative HTML version deleted]]
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
On the off chance that anyone is still interested, here is the corrected function using aperm(): z <- array(1:120,dim=2:5) f2 <- function(a, wh) { idx <- seq_len(length(dim(a))) dims <- setdiff(idx, wh) idx <- append(idx[-1], idx[1], wh-1) aperm(apply(a, dims, rev), idx) } all.equal(f(z, 1), f2(z, 1)) # [1] TRUE all.equal(f(z, 2), f2(z, 2)) # [1] TRUE