You mentioned data.frame at one place and matrix at another. Matrix would be faster.
#Speed comparison #Speed set.seed(1454) dfTest<- as.data.frame(matrix(sample(LETTERS[15:18],5*1e6,replace=TRUE),ncol=5)) system.time(res<-dfTest[rowSums(dfTest=="P")==ncol(dfTest),]) # user system elapsed # 0.628 0.020 0.649 dim(res) #[1] 952 5 set.seed(1454) mat1<- matrix(sample(LETTERS[15:18],5*1e6,replace=TRUE),ncol=5) system.time(res1<-mat1[rowSums(mat1=="P")==ncol(mat1),]) # user system elapsed # 0.188 0.004 0.194 dim(res1) #[1] 952 5 #Other options include system.time(res3<- dfTest[apply(sweep(dfTest,1,"P","=="),1,all),]) # user system elapsed # 5.988 0.120 6.120 identical(res,res3) #[1] TRUE system.time(res2<- dfTest[apply(dfTest,1, function(x) all(length(table(x))==ncol(dfTest) | names(table(x))=="P") ), ]) # user system elapsed #351.492 0.040 352.164 row.names(res2)<- row.names(res3) attr(res3,"row.names")<- attr(res2,"row.names") identical(res2,res3) #[1] TRUE A.K. ----- Original Message ----- From: arun <smartpink...@yahoo.com> To: Chirag Gupta <cxg...@email.uark.edu> Cc: R help <r-help@r-project.org> Sent: Monday, July 15, 2013 9:23 PM Subject: Re: [R] Deleting specific rows from a dataframe Hi, If I understand it correctly, df1<- read.table(text=" sample1 sample2 sample3 sample4 sample5 a P P I P P b P A P P A c P P P P P d P P P P P e M P M A P f P P P P P g P P P A P h P P P P P ",sep="",header=TRUE,stringsAsFactors=FALSE) df1[rowSums(df1=="P")==ncol(df1),] # sample1 sample2 sample3 sample4 sample5 #c P P P P P #d P P P P P #f P P P P P #h P P P P P A.K. ----- Original Message ----- From: Chirag Gupta <cxg...@email.uark.edu> To: r-help@r-project.org Cc: Sent: Monday, July 15, 2013 9:10 PM Subject: [R] Deleting specific rows from a dataframe I have a data frame like shown below sample1 sample2 sample3 sample4 sample5 a P P I P P b P A P P A c P P P P P d P P P P P e M P M A P f P P P P P g P P P A P h P P P P P I want to keep only those rows which have all "P" across all the columns. Since the matrix is large (about 20,000 rows), I cannot do it in excel Any special function that i can use? -- *Chirag Gupta* [[alternative HTML version deleted]] ______________________________________________ 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.
