[R] subset a matrix
Dear friends, I have a (20*30) matrix,and want to get a subset of it like the following: The original matrix: rows:1,2,3,20; columns:1,2,3,30 I want to get my subset of The original matrix and delete others: rows:1,3,5,7,...19; columns:1,3,5.29 -- Kind Regards,Zhi Jie,Zhang ,PHDDepartment of EpidemiologySchool of Public HealthFudan UniversityTel:86-21-54237149 [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] subset a matrix
Assuming that you want odd-numbered rows/cols, the seq() function is handy, as in: mat - matrix(1:(20*30), nr = 20) mat1 - mat[seq(1, 19, by = 2), seq(1, 29, by = 2)] Peter Ehlers zhijie zhang wrote: Dear friends, I have a (20*30) matrix,and want to get a subset of it like the following: The original matrix: rows:1,2,3,20; columns:1,2,3,30 I want to get my subset of The original matrix and delete others: rows:1,3,5,7,...19; columns:1,3,5.29 -- Kind Regards,Zhi Jie,Zhang ,PHDDepartment of EpidemiologySchool of Public HealthFudan UniversityTel:86-21-54237149 [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] subset a matrix
x=matrix(rnorm(20*30),20) y=x[seq(1,20,by=2),seq(1,30,by=2)] 2006/4/12, zhijie zhang [EMAIL PROTECTED]: Dear friends, I have a (20*30) matrix,and want to get a subset of it like the following: The original matrix: rows:1,2,3,20; columns:1,2,3,30 I want to get my subset of The original matrix and delete others: rows:1,3,5,7,...19; columns:1,3,5.29 -- Kind Regards,Zhi Jie,Zhang ,PHDDepartment of EpidemiologySchool of Public HealthFudan UniversityTel:86-21-54237149 [[alternative HTML version deleted]] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html -- 黄荣贵 Deparment of Sociology Fudan University __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
