Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
On 2020-04-03 07:39 +1100, Jim Lemon wrote: | | Hi Rasmus, | Very nice. The R help list is a bit like a | quiz show where the contestants must | balance the alacrity with which they press | their buttons with the confidence that they | have the correct answer. A slow motion game | of wits in which the prizes are | self-awarded. Hi Jim, Thank you. I try my best to understand the question at hand, and thus can only hope to nail a right balance on this alacrity-confidence quiz show scale or yours :) I'm glad if this could help us understand R better. Regards, Rasmus __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
On 2020-04-01 15:33 +1100, Jim Lemon wrote:
> Hi Nevil,
> It's a nasty piece of work, but:
Hi! How about this one:
data <- c(rep(1:4, times=3), 2, 1, 3, 2)
dimnames <- list(NULL, c("x", "y", "z", "k"))
ncol <- length(data)/4
M <- matrix(data=data, nrow=ncol, ncol=ncol, dimnames=dimnames)
FUN <- function(x) {
out <- matrix(rep(x[1:3], times=x[4]),
byrow=TRUE, nrow=x[4])
return(cbind(out, x[4]))
}
newM <- do.call(rbind, apply(X=M, MARGIN=1, FUN=FUN))
dimnames(newM) <- list(NULL, c("x", "y", "z", "k"))
newM <- cbind(newM, "j"=sequence(M[,"k"]))
newM
Regards,
Rasmus
__
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Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
Hi Rasmus,
Very nice. The R help list is a bit like a quiz show where the
contestants must balance the alacrity with which they press their
buttons with the confidence that they have the correct answer. A slow
motion game of wits in which the prizes are self-awarded.
Jim
On Fri, Apr 3, 2020 at 7:04 AM Rasmus Liland wrote:
>
> On 2020-04-01 15:33 +1100, Jim Lemon wrote:
> > Hi Nevil,
> > It's a nasty piece of work, but:
>
> Hi! How about this one:
>
> data <- c(rep(1:4, times=3), 2, 1, 3, 2)
> dimnames <- list(NULL, c("x", "y", "z", "k"))
> ncol <- length(data)/4
> M <- matrix(data=data, nrow=ncol, ncol=ncol, dimnames=dimnames)
>
> FUN <- function(x) {
> out <- matrix(rep(x[1:3], times=x[4]),
> byrow=TRUE, nrow=x[4])
> return(cbind(out, x[4]))
> }
> newM <- do.call(rbind, apply(X=M, MARGIN=1, FUN=FUN))
> dimnames(newM) <- list(NULL, c("x", "y", "z", "k"))
> newM <- cbind(newM, "j"=sequence(M[,"k"]))
> newM
>
> Regards,
> Rasmus
__
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Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
Hi Nevil,
It's a nasty piece of work, but:
M<-matrix(c(1,2,3,4,1,2,3,4,1,2,3,4,2,1,3,2),4,4,
dimnames = list(NULL, c("x", "y", "z","k")))
M
reprow<-function(x)
return(matrix(rep(x,x[length(x)]),nrow=x[length(x)],byrow=TRUE))
toseq<-function(x) return(1:x)
j<-unlist(sapply(M[,"k"],toseq))
Mlist<-apply(M,1,reprow)
Mlist
newM<-Mlist[[1]]
for(i in 2:length(Mlist)) newM<-rbind(newM,Mlist[[i]])
newM
newM<-cbind(newM,j)
colnames(newM)<-c(colnames(M),"j")
newM
Jim
On Wed, Apr 1, 2020 at 1:43 PM nevil amos wrote:
>
> Well,
> I found a way to do it partly using rep(), and one loop that makes it 10x
> or more faster however would still be good to do without the loop at all
> matrix made slightly beigger (1 rows):
>
> M<-matrix(c(1:3
> ), 1,3)
> M<-cbind(M,sample(1:5,size = 1,replace = T))
> #Print(M)
> #Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
> #repeated k times with column j numbered from 1:k
> # ! can do with nested loops but this is very slow ( example below)
> #How do I acheive this quickly without loops?
> print("double loop")
> print(system.time({
> Mout<-NULL
>
> for(i in 1:nrow(M)){
> a=M[i,1:3]
> k=M[i,4]
> for (j in 1:k){
> b=c(a,j)
> Mout<-rbind(Mout,b)
> }
> }
> colnames(Mout)<-c("x","y","z","j")
> }))
>
> print("rep and single loop")
> print(system.time({
> j<-NULL
> MOut<-NULL
> MOut<-M[,1:3][rep(1:nrow(M), times = M[,4]), ]
> for(i in M[,4])(j<-c(j,1:i))
> MOut<-cbind(MOut,j)
> colnames(Mout)<-c("x","y","z","j")
> }))
>
> On Wed, 1 Apr 2020 at 12:18, nevil amos wrote:
>
> > Hi
> >
> > I can achieve this using two for loops but it is slow I need to do this
> > on many matrices with tens of millions of rows of x,y,z and k
> >
> > What is a faster method to achieve this, I cannot use rep as j changes in
> > each row of the new matrix
> > ###
> > M<-matrix(c(1,2,3,4,1,2,3,4,1,2,3,4, 2, 1, 3, 2
> > ), 4,4, dimnames = list(NULL, c("x", "y", "z","k")))
> >
> > Print(M)
> > #Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
> > #repeated k times with column j numbered from 1:k
> > # ! can do with nested loops but this is very slow ( example below)
> > #How do I acheive this quickly without loops?
> > Mout<-NULL
> >
> > for(i in 1:nrow(M)){
> > a=M[i,c("x","y","z")]
> > for (j in 1:M[i,"k"]){
> > b=c(a,j)
> > Mout<-rbind(Mout,b)
> > }
> > }
> > colnames(Mout)[4]<-"j"
> > print(Mout)
> >
> > #
> >
> > Thanks
> >
> > Nevil Amos
> >
>
> [[alternative HTML version deleted]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
OK sorted - hope these postings might help someone else
Any even faster options would be appreciated still
#seq() does not work but sequence() does
print("rep and sequence")
print(system.time({
j<-NULL
MOut<-NULL
MOut<-M[rep(1:nrow(M), times = M[,4]), ]
j<-sequence(M[,4])
MOut<-cbind(MOut,j)
colnames(Mout)<-c("x","y","z","j")
}))
On Wed, 1 Apr 2020 at 13:42, nevil amos wrote:
> Well,
> I found a way to do it partly using rep(), and one loop that makes it 10x
> or more faster however would still be good to do without the loop at all
> matrix made slightly beigger (1 rows):
>
> M<-matrix(c(1:3
> ), 1,3)
> M<-cbind(M,sample(1:5,size = 1,replace = T))
> #Print(M)
> #Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
> #repeated k times with column j numbered from 1:k
> # ! can do with nested loops but this is very slow ( example below)
> #How do I acheive this quickly without loops?
> print("double loop")
> print(system.time({
> Mout<-NULL
>
> for(i in 1:nrow(M)){
> a=M[i,1:3]
> k=M[i,4]
> for (j in 1:k){
> b=c(a,j)
> Mout<-rbind(Mout,b)
> }
> }
> colnames(Mout)<-c("x","y","z","j")
> }))
>
> print("rep and single loop")
> print(system.time({
> j<-NULL
> MOut<-NULL
> MOut<-M[,1:3][rep(1:nrow(M), times = M[,4]), ]
> for(i in M[,4])(j<-c(j,1:i))
> MOut<-cbind(MOut,j)
> colnames(Mout)<-c("x","y","z","j")
> }))
>
> On Wed, 1 Apr 2020 at 12:18, nevil amos wrote:
>
>> Hi
>>
>> I can achieve this using two for loops but it is slow I need to do this
>> on many matrices with tens of millions of rows of x,y,z and k
>>
>> What is a faster method to achieve this, I cannot use rep as j changes in
>> each row of the new matrix
>> ###
>> M<-matrix(c(1,2,3,4,1,2,3,4,1,2,3,4, 2, 1, 3, 2
>> ), 4,4, dimnames = list(NULL, c("x", "y", "z","k")))
>>
>> Print(M)
>> #Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
>> #repeated k times with column j numbered from 1:k
>> # ! can do with nested loops but this is very slow ( example below)
>> #How do I acheive this quickly without loops?
>> Mout<-NULL
>>
>> for(i in 1:nrow(M)){
>> a=M[i,c("x","y","z")]
>> for (j in 1:M[i,"k"]){
>> b=c(a,j)
>> Mout<-rbind(Mout,b)
>> }
>> }
>> colnames(Mout)[4]<-"j"
>> print(Mout)
>>
>> #
>>
>> Thanks
>>
>> Nevil Amos
>>
>
[[alternative HTML version deleted]]
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and provide commented, minimal, self-contained, reproducible code.
Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
Well,
I found a way to do it partly using rep(), and one loop that makes it 10x
or more faster however would still be good to do without the loop at all
matrix made slightly beigger (1 rows):
M<-matrix(c(1:3
), 1,3)
M<-cbind(M,sample(1:5,size = 1,replace = T))
#Print(M)
#Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
#repeated k times with column j numbered from 1:k
# ! can do with nested loops but this is very slow ( example below)
#How do I acheive this quickly without loops?
print("double loop")
print(system.time({
Mout<-NULL
for(i in 1:nrow(M)){
a=M[i,1:3]
k=M[i,4]
for (j in 1:k){
b=c(a,j)
Mout<-rbind(Mout,b)
}
}
colnames(Mout)<-c("x","y","z","j")
}))
print("rep and single loop")
print(system.time({
j<-NULL
MOut<-NULL
MOut<-M[,1:3][rep(1:nrow(M), times = M[,4]), ]
for(i in M[,4])(j<-c(j,1:i))
MOut<-cbind(MOut,j)
colnames(Mout)<-c("x","y","z","j")
}))
On Wed, 1 Apr 2020 at 12:18, nevil amos wrote:
> Hi
>
> I can achieve this using two for loops but it is slow I need to do this
> on many matrices with tens of millions of rows of x,y,z and k
>
> What is a faster method to achieve this, I cannot use rep as j changes in
> each row of the new matrix
> ###
> M<-matrix(c(1,2,3,4,1,2,3,4,1,2,3,4, 2, 1, 3, 2
> ), 4,4, dimnames = list(NULL, c("x", "y", "z","k")))
>
> Print(M)
> #Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
> #repeated k times with column j numbered from 1:k
> # ! can do with nested loops but this is very slow ( example below)
> #How do I acheive this quickly without loops?
> Mout<-NULL
>
> for(i in 1:nrow(M)){
> a=M[i,c("x","y","z")]
> for (j in 1:M[i,"k"]){
> b=c(a,j)
> Mout<-rbind(Mout,b)
> }
> }
> colnames(Mout)[4]<-"j"
> print(Mout)
>
> #
>
> Thanks
>
> Nevil Amos
>
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] repeat rows of matrix by number (k) in one colummatrix adding column j with values 1:k
False premise: rep works fine
Mout2 <- cbind(M[ rep(seq.int(nrow(M)),M[,"k"]),
c("x","y","z")],unlist(lapply(M[,"k"],seq.int)))
On March 31, 2020 6:18:37 PM PDT, nevil amos wrote:
>Hi
>
>I can achieve this using two for loops but it is slow I need to do
>this on
>many matrices with tens of millions of rows of x,y,z and k
>
>What is a faster method to achieve this, I cannot use rep as j changes
>in
>each row of the new matrix
>###
>M<-matrix(c(1,2,3,4,1,2,3,4,1,2,3,4, 2, 1, 3, 2
>), 4,4, dimnames = list(NULL, c("x", "y", "z","k")))
>
>Print(M)
>#Create matrix (Mout) in this case 8 rows with x,y,z in each row of M
>#repeated k times with column j numbered from 1:k
># ! can do with nested loops but this is very slow ( example below)
>#How do I acheive this quickly without loops?
>Mout<-NULL
>
>for(i in 1:nrow(M)){
> a=M[i,c("x","y","z")]
> for (j in 1:M[i,"k"]){
>b=c(a,j)
>Mout<-rbind(Mout,b)
>}
>}
>colnames(Mout)[4]<-"j"
>print(Mout)
>
>#
>
>Thanks
>
>Nevil Amos
>
> [[alternative HTML version deleted]]
>
>__
>R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
--
Sent from my phone. Please excuse my brevity.
__
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