> mat[,colSums(mat!=0)>=5] Jacques VESLOT
CEMAGREF - UR Hydrobiologie Route de Cézanne - CS 40061 13182 AIX-EN-PROVENCE Cedex 5, France Tél. + 0033 04 42 66 99 76 fax + 0033 04 42 66 99 34 email jacques.ves...@cemagref.fr >-----Message d'origine----- >De : r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] De la >part >de Bob Green >Envoyé : mercredi 24 décembre 2008 13:17 >À : r-help@r-project.org >Objet : [R] selecting a subset of a matrix based on a value occurring in 5 >records > > >Hello, > >>I am hoping for some advice as to how I might create a subset of a >>matrix. The matrix is 176 x 3530. The rows are individual records >>and the columns words. I want to create a new matrix that only >>consists of words which occur in at least 5 records. For example, >>if column 7 is "charges" and this only appears in 4 records/rows >>this variable would not be included, whereas if column 109 was the >>word "monitor" and occurred in 95 records it would be saved into the >>new matrix. Values in the matrix are numbers, such that if a word >>does not occur in a record the cell contains a zero, whereas if it >>occurs 7 times there is a value of 7 for that record. It is the >>number of records rather than the than the column total that is the >>criteria for determing inclusion into the matrix. > > >Any suggestions on how I might reduce the size of this matrix so as >to include only those columns in which a word occurs at least in 5 >records is much appreciated, > >regards > >Bob > >______________________________________________ >R-help@r-project.org mailing list >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. ______________________________________________ R-help@r-project.org mailing list 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.