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Muhammad Subianto

2006-Aug-24 16:59 UTC

[R] Check values in colums matrix

Dear all,
I apologize if my question is quite simple.
I have a dataset (20 columns & 1000 rows) which
some of columns have the same value and the others
have different values.
Here are some piece of my dataset:
obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
             c(0,1,1,4,1,0,1,4,-1),
             c(1,1,1,4,2,0,1,4,-1),
             c(1,1,1,4,3,0,1,4,-1),
             c(1,1,1,4,6,0,1,5,-1),
             c(1,1,1,4,6,0,1,6,-1),
             c(1,1,1,4,6,0,1,7,-1),
             c(1,1,1,4,6,0,1,8,-1))
obj.tr <- t(obj)
obj.tr> obj.tr     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
[1,]    1    1    1    4    0    0    1    4   -1
[2,]    0    1    1    4    1    0    1    4   -1
[3,]    1    1    1    4    2    0    1    4   -1
[4,]    1    1    1    4    3    0    1    4   -1
[5,]    1    1    1    4    6    0    1    5   -1
[6,]    1    1    1    4    6    0    1    6   -1
[7,]    1    1    1    4    6    0    1    7   -1
[8,]    1    1    1    4    6    0    1    8   -1>
How can I do to check columns 2,3,4,6,7 and 9 have
the same value, and columns 1,5 and 8 have different values.

Best, Muhammad Subianto

Paul Smith

2006-Aug-24 21:07 UTC

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[R] Check values in colums matrix

On 8/24/06, Muhammad Subianto <msubianto at gmail.com>
wrote:> I have a dataset (20 columns & 1000 rows) which
> some of columns have the same value and the others
> have different values.
> Here are some piece of my dataset:
> obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
>              c(0,1,1,4,1,0,1,4,-1),
>              c(1,1,1,4,2,0,1,4,-1),
>              c(1,1,1,4,3,0,1,4,-1),
>              c(1,1,1,4,6,0,1,5,-1),
>              c(1,1,1,4,6,0,1,6,-1),
>              c(1,1,1,4,6,0,1,7,-1),
>              c(1,1,1,4,6,0,1,8,-1))
> obj.tr <- t(obj)
> obj.tr
> > obj.tr
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
> [1,]    1    1    1    4    0    0    1    4   -1
> [2,]    0    1    1    4    1    0    1    4   -1
> [3,]    1    1    1    4    2    0    1    4   -1
> [4,]    1    1    1    4    3    0    1    4   -1
> [5,]    1    1    1    4    6    0    1    5   -1
> [6,]    1    1    1    4    6    0    1    6   -1
> [7,]    1    1    1    4    6    0    1    7   -1
> [8,]    1    1    1    4    6    0    1    8   -1
> >
>
> How can I do to check columns 2,3,4,6,7 and 9 have
> the same value, and columns 1,5 and 8 have different values.
Just try

all(obj.tr[,2]==obj.tr[1,2])

and so on for the other columns. See ? all.

Paul

John Kane

2006-Aug-24 21:52 UTC

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[R] Check values in colums matrix

--- Muhammad Subianto <msubianto at gmail.com> wrote:
> Dear all,
> I apologize if my question is quite simple.
> I have a dataset (20 columns & 1000 rows) which
> some of columns have the same value and the others
> have different values.
> Here are some piece of my dataset:
> obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
>              c(0,1,1,4,1,0,1,4,-1),
>              c(1,1,1,4,2,0,1,4,-1),
>              c(1,1,1,4,3,0,1,4,-1),
>              c(1,1,1,4,6,0,1,5,-1),
>              c(1,1,1,4,6,0,1,6,-1),
>              c(1,1,1,4,6,0,1,7,-1),
>              c(1,1,1,4,6,0,1,8,-1))
> obj.tr <- t(obj)
> obj.tr
> > obj.tr
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
> [1,]    1    1    1    4    0    0    1    4   -1
> [2,]    0    1    1    4    1    0    1    4   -1
> [3,]    1    1    1    4    2    0    1    4   -1
> [4,]    1    1    1    4    3    0    1    4   -1
> [5,]    1    1    1    4    6    0    1    5   -1
> [6,]    1    1    1    4    6    0    1    6   -1
> [7,]    1    1    1    4    6    0    1    7   -1
> [8,]    1    1    1    4    6    0    1    8   -1
> >
> 
> How can I do to check columns 2,3,4,6,7 and 9 have
> the same value, and columns 1,5 and 8 have different
> values.
> 
> Best, Muhammad Subianto There has to be a better way but this will let you
check visually since you only have 20 columns

for(i in 1:8) {
tt <-table(obj.tr[,i])
print( i)
print (tt)
}

Gabor Grothendieck

2006-Aug-24 23:27 UTC

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[R] Check values in colums matrix

Try sd(obj.tr) which will give a vector of standard deviations, one per column.
A column's entry will be zero if and only if all values in the column
are the same.

On 8/24/06, Muhammad Subianto <msubianto at gmail.com>
wrote:> Dear all,
> I apologize if my question is quite simple.
> I have a dataset (20 columns & 1000 rows) which
> some of columns have the same value and the others
> have different values.
> Here are some piece of my dataset:
> obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
>             c(0,1,1,4,1,0,1,4,-1),
>             c(1,1,1,4,2,0,1,4,-1),
>             c(1,1,1,4,3,0,1,4,-1),
>             c(1,1,1,4,6,0,1,5,-1),
>             c(1,1,1,4,6,0,1,6,-1),
>             c(1,1,1,4,6,0,1,7,-1),
>             c(1,1,1,4,6,0,1,8,-1))
> obj.tr <- t(obj)
> obj.tr
> > obj.tr
>     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
> [1,]    1    1    1    4    0    0    1    4   -1
> [2,]    0    1    1    4    1    0    1    4   -1
> [3,]    1    1    1    4    2    0    1    4   -1
> [4,]    1    1    1    4    3    0    1    4   -1
> [5,]    1    1    1    4    6    0    1    5   -1
> [6,]    1    1    1    4    6    0    1    6   -1
> [7,]    1    1    1    4    6    0    1    7   -1
> [8,]    1    1    1    4    6    0    1    8   -1
> >
>
> How can I do to check columns 2,3,4,6,7 and 9 have
> the same value, and columns 1,5 and 8 have different values.
>
> Best, Muhammad Subianto
>
> ______________________________________________
> R-help at 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
> and provide commented, minimal, self-contained, reproducible code.
>

Bill.Venables at csiro.au

2006-Aug-25 03:39 UTC

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[R] Check values in colums matrix

As a minor footnote to both of these, I would add that both assume
that all the columns of the dataset are numeric.  It doesn't cost much
to generalize it to cover any matrix structure, of any mode:

constantColmuns <- function(Xmat) 
    which(apply(Xmat, 2, function(z) length(unique(z)) == 1))
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Berton
Gunter> Sent: Friday, 25 August 2006 9:37 AM
> To: 'Gabor Grothendieck'; 'Muhammad Subianto'
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] Check values in colums matrix
> 
> Absolutely. But do note that if the values in obj are the product of
> numerical computations then columns of equal values may turn out to be
only> **nearly** equal and so the sd may turn out to be **nearly** 0 and not
> exactly 0. This is a standard issue in numerical computation, of
course, and> has been commented on in this list at least dozens of times, but it's
still> a gotcha for the unwary (so now dozens +1).
> 
> -- Bert Gunter
> Genentech Non-Clinical Statistics
> South San Francisco, CA
>  
>  
> 
> > -----Original Message-----
> > From: r-help-bounces at stat.math.ethz.ch 
> > [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Gabor 
> > Grothendieck
> > Sent: Thursday, August 24, 2006 4:28 PM
> > To: Muhammad Subianto
> > Cc: r-help at stat.math.ethz.ch
> > Subject: Re: [R] Check values in colums matrix
> > 
> > Try sd(obj.tr) which will give a vector of standard 
> > deviations, one per column.
> > A column's entry will be zero if and only if all values in the
column> > are the same.
> > 
> > On 8/24/06, Muhammad Subianto <msubianto at gmail.com> wrote:
> > > Dear all,
> > > I apologize if my question is quite simple.
> > > I have a dataset (20 columns & 1000 rows) which
> > > some of columns have the same value and the others
> > > have different values.
> > > Here are some piece of my dataset:
> > > obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
> > >             c(0,1,1,4,1,0,1,4,-1),
> > >             c(1,1,1,4,2,0,1,4,-1),
> > >             c(1,1,1,4,3,0,1,4,-1),
> > >             c(1,1,1,4,6,0,1,5,-1),
> > >             c(1,1,1,4,6,0,1,6,-1),
> > >             c(1,1,1,4,6,0,1,7,-1),
> > >             c(1,1,1,4,6,0,1,8,-1))
> > > obj.tr <- t(obj)
> > > obj.tr
> > > > obj.tr
> > >     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
> > > [1,]    1    1    1    4    0    0    1    4   -1
> > > [2,]    0    1    1    4    1    0    1    4   -1
> > > [3,]    1    1    1    4    2    0    1    4   -1
> > > [4,]    1    1    1    4    3    0    1    4   -1
> > > [5,]    1    1    1    4    6    0    1    5   -1
> > > [6,]    1    1    1    4    6    0    1    6   -1
> > > [7,]    1    1    1    4    6    0    1    7   -1
> > > [8,]    1    1    1    4    6    0    1    8   -1
> > > >
> > >
> > > How can I do to check columns 2,3,4,6,7 and 9 have
> > > the same value, and columns 1,5 and 8 have different values.
> > >
> > > Best, Muhammad Subianto

Muhammad Subianto

2006-Aug-25 08:28 UTC

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[R] Check values in colums matrix

Dear all,
I would like to thank everybody who replied for their useful 
suggestions. Maybe, I am going through the book statistics to teach 
(fresh) myself.
Wish you have a nice weekend.

Regards, Muhammad Subianto


On this day 24/08/2006 18:59, Muhammad Subianto wrote:> Dear all,
> I apologize if my question is quite simple.
> I have a dataset (20 columns & 1000 rows) which
> some of columns have the same value and the others
> have different values.
> Here are some piece of my dataset:
> obj <- cbind(c(1,1,1,4,0,0,1,4,-1),
>              c(0,1,1,4,1,0,1,4,-1),
>              c(1,1,1,4,2,0,1,4,-1),
>              c(1,1,1,4,3,0,1,4,-1),
>              c(1,1,1,4,6,0,1,5,-1),
>              c(1,1,1,4,6,0,1,6,-1),
>              c(1,1,1,4,6,0,1,7,-1),
>              c(1,1,1,4,6,0,1,8,-1))
> obj.tr <- t(obj)
> obj.tr
>> obj.tr
>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
> [1,]    1    1    1    4    0    0    1    4   -1
> [2,]    0    1    1    4    1    0    1    4   -1
> [3,]    1    1    1    4    2    0    1    4   -1
> [4,]    1    1    1    4    3    0    1    4   -1
> [5,]    1    1    1    4    6    0    1    5   -1
> [6,]    1    1    1    4    6    0    1    6   -1
> [7,]    1    1    1    4    6    0    1    7   -1
> [8,]    1    1    1    4    6    0    1    8   -1
> 
> How can I do to check columns 2,3,4,6,7 and 9 have
> the same value, and columns 1,5 and 8 have different values.
> 
> Best, Muhammad Subianto
> 
> ______________________________________________
> R-help at 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
> and provide commented, minimal, self-contained, reproducible code.
>

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