Message-ID: <644e1f320903260438u4c9225tc6f3f3008d28dfa2@mail.gmail.com>
Date: 2009-03-26T11:38:12Z
From: jim holtman
Subject: same value in column-->delete
In-Reply-To: <4CDCB6746FDEE34CA66F8B557440A60AC7F670CB45@ipgpost.ipg.lan>
Try this:
> x
id snp1 snp2 snp3
1 1 A G G
2 2 G G G
3 3 G G A
> str(x)
'data.frame': 3 obs. of 4 variables:
$ id : num 1 2 3
$ snp1: Factor w/ 2 levels "A","G": 1 2 2
$ snp2: Factor w/ 1 level "G": 1 1 1
$ snp3: Factor w/ 2 levels "A","G": 2 2 1
> # test for which columns are the same
> apply(x, 2, function(.col) all(head(.col, -1) == tail(.col, -1)))
id snp1 snp2 snp3
FALSE FALSE TRUE FALSE
>
On Thu, Mar 26, 2009 at 7:15 AM, Duijvesteijn, Naomi
<Naomi.Duijvesteijn at ipg.nl> wrote:
>
> ? Hi Readers,
>
>
> ? I have a question.
>
>
> ? I have a large dataset and want to throw away columns that have the same
> ? value in the column itself and I want to know which column this was.
>
>
> ? For example
>
> ? > x<-data.frame(id=c(1,2,3), snp1=c("A","G",
> ? "G"),snp2=c("G","G","G"),snp3=c("G","G","A"))
>
> ? > x
>
> ? ? id snp1 snp2 snp3
>
> ? 1 ?1 ? ?A ? ?G ? ?G
>
> ? 2 ?2 ? ?G ? ?G ? ?G
>
> ? 3 ?3 ? ?G ? ?G ? ?A
>
>
> ? Now I want to know that snp2 in monomorphic (the same value for the column)
> ? and after I know which column it is I want to take these columns out.
>
>
> ? Thanks,
>
> ? Naomi
>
>
>
>
>
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--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?