Yes. If you want repeated calls to sample() you need to call it several times.
Try, for instance replicate(5, sample(1:10)) which is nearly the structure you expected, except transposed. -pd > On 13 Mar 2025, at 22.33, Bert Gunter <bgunter.4...@gmail.com> wrote: > > Bravo for your unrequired R efforts. > > You misunderstand the nested call. sample() is called only once, > producing 1 sample of 10 with replacement. Since your matrix call > needs 50 values, ?matrix tells you (in details): > "If there are too few elements in data to fill the matrix, then the > elements in data are recycled. If data has length zero, NA of an > appropriate type is used for atomic vectors (0 for raw vectors) and > NULL for lists. > > This sort of "recycling" is quite standard in R. Though not universal. > > Cheers, > Bert > > "An educated person is one who can entertain new ideas, entertain > others, and entertain herself." > > On Thu, Mar 13, 2025 at 2:23 PM Kevin Zembower via R-help > <r-help@r-project.org> wrote: >> >> Hello, all, >> >> I'm learning to do randomized distributions in my Stats 101 class*. I >> thought I could do it with a call to sample() inside a matrix(), like: >> >>> matrix(sample(1:10, replace=TRUE), 5, 10, byrow=TRUE) >> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] >> [1,] 8 2 3 1 8 2 8 8 9 8 >> [2,] 8 2 3 1 8 2 8 8 9 8 >> [3,] 8 2 3 1 8 2 8 8 9 8 >> [4,] 8 2 3 1 8 2 8 8 9 8 >> [5,] 8 2 3 1 8 2 8 8 9 8 >>> >> >> Imagine my surprise to learn that all the rows were the same >> permutation. I thought each time sample() was called inside the matrix, >> it would generate a different permutation. >> >> I modeled this after the bootstrap sample techniques in >> https://pages.stat.wisc.edu/~larget/stat302/chap3.pdf. I don't >> understand why it works in bootstrap samples (with replace=TRUE), but >> not in randomized distributions (with replace=FALSE). >> >> Thanks for any insight you can share with me, and any suggestions for >> getting rows in a matrix with different permutations. >> >> -Kevin >> >> *No, this isn't a homework problem. We're using Lock5 as the text in >> class, along with its StatKey web application. I'm just trying to get >> more out of the class by also solving our problems using R, for which >> I'm not receiving any class credit. >> >> ______________________________________________ >> 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 https://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > 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 https://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business SchoolSolbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ 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 https://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
