[R] [Q] It it possible to create the data frame only non-zero data column?
Hiroyuki Sato
hiroysato at gmail.com
Tue Jan 12 03:37:12 CET 2016
Hello Ulrik, Ashis and Petr
Thank you for replying.
I'll use dat[dat==0] <- NA.
Thanks
2016年1月11日(月) 16:17 PIKAL Petr <petr.pikal at precheza.cz>:
> Hi
>
> as.matrix is rather dangerous, it converts all values to lowest mode
> which, if there is text column, is character.
>
> And if I understand correctly original post was about removing all zero
> columns.
>
> Using plain zero comparison can be dangerous due to possibility of
> compensating negative and positive values.
> > dat<-data.frame(a=c(-1,0,1), b=c(0,0,0), c=c(0,0,1))
> > dat
> a b c
> 1 -1 0 0
> 2 0 0 0
> 3 1 0 1
> > colSums(dat)==0
> a b c
> TRUE TRUE FALSE
>
> Remove incorrectly first column too.
>
> I would proceed with NA substitution, which is safer.
>
> > dat[dat==0]<-NA
> > colSums(is.na(dat))==nrow(dat)
> a b c
> FALSE TRUE FALSE
> >
>
> And even this can be problematic if values in dat are not integers.
>
> Cheers
> Petr
>
> > -----Original Message-----
> > From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Ulrik
> > Stervbo
> > Sent: Friday, January 08, 2016 6:06 PM
> > To: Hiroyuki Sato; r-help at r-project.org
> > Subject: Re: [R] [Q] It it possible to create the data frame only non-
> > zero data column?
> >
> > Could you use rowsum and select rows larger then 0?
> >
> > Something like:
> >
> > result[rowsum(as.matrix(result) > 0, ]
> >
> > On Fri, 8 Jan 2016 at 18:00 Hiroyuki Sato <hiroysato at gmail.com> wrote:
> >
> > > Hello all.
> > >
> > > I re-post this question by e-mail.
> > > (I posted via google-group. But It's not posted yet.)
> > >
> > > I'm newbie GNU R.
> > >
> > > I would like to compare two datas.
> > > How to select columns which has non-zero datas?.
> > > It it possible to create the data frame only VAL3(non-zero data)
> > > column with command?
> > >
> > > Formatted sample.
> > > https://gist.github.com/hiroyuki-sato/cb36584f6cd5845b6c3e
> > >
> > > sample1.txt
> > >
> > > ID,VAL1,VAL2,VAL3
> > > ID1,0,2,3
> > > ID2,0,2,3
> > > ID3,0,2,3
> > >
> > > real data has 5000 columns.
> > >
> > > sample2.txt
> > >
> > > ID,VAL1,VAL2,VAL3
> > > ID1,0,2,3
> > > ID2,0,2,3
> > > ID3,0,2,2
> > >
> > > The difference sample1 and sample2 is ID3/VAL3.
> > > sample1: 3
> > > sample2: 2
> > >
> > > R commands.
> > >
> > > sample1 <- read.table("sample1.txt",header=T,sep=',')
> > > sample2 <- read.table("sample2.txt",header=T,sep=',')
> > >
> > > result <- sample1[,2:4] - sample2[,2:4]
> > > result
> > > VAL1 VAL2 VAL3
> > > 1 0 0 0
> > > 2 0 0 0
> > > 3 0 0 1
> > >
> > > I would like to create data frame which has non-zero value columns.
> > > Could you tell me how to do it?
> > >
> > > Best regards.
> > >
> > > --
> > > Hiroyuki Sato.
> > >
> > > [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
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