[R] matrix manipulation question

PIKAL Petr
Fri, 27 Mar 2015 11:34:19 -0000

Very, very, very bad solution.

as.matrix can change silently your data to unwanted format, complete.cases()==T
is silly as Peter already pointed out.

I use

head(airquality[ ,colSums(is.na(airquality))==0])
  Wind Temp Month Day
1  7.4   67     5   1
2  8.0   72     5   2
3 12.6   74     5   3
4 11.5   62     5   4
5 14.3   56     5   5
6 14.9   66     5   6

if I want to get rid of columns with NA.

Cheers
Petr


From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of St?phane
Adamowicz
Sent: Friday, March 27, 2015 11:42 AM
To: peter dalgaard
Cc: r-help at r-project.org
Subject: Re: [R] matrix manipulation question

Well, it seems to work with me.

Y <- as.matrix(airquality)
head(Y, n=8)
     Ozone Solar.R Wind Temp Month Day
[1,]    41     190  7.4   67     5   1
[2,]    36     118  8.0   72     5   2
[3,]    12     149 12.6   74     5   3
[4,]    18     313 11.5   62     5   4
[5,]    NA      NA 14.3   56     5   5
[6,]    28      NA 14.9   66     5   6
[7,]    23     299  8.6   65     5   7
[8,]    19      99 13.8   59     5   8

Z <- Y[,complete.cases(t(Y))==T]

head(Z, n=8)
     Wind Temp Month Day
[1,]  7.4   67     5   1
[2,]  8.0   72     5   2
[3,] 12.6   74     5   3
[4,] 11.5   62     5   4
[5,] 14.3   56     5   5
[6,] 14.9   66     5   6
[7,]  8.6   65     5   7
[8,] 13.8   59     5   8

The columns that contained NA were deleted.


Le 27 mars 2015 ? 10:38, peter dalgaard <pdalgd at gmail.com<mailto:pdalgd
at gmail.com>> a ?crit :

>
> On 27 Mar 2015, at 09:58 , St?phane Adamowicz <stephane.adamowicz at
avignon.inra.fr<mailto:stephane.adamowicz at avignon.inra.fr>> wrote:
>
>> data_no_NA <- data[, complete.cases(t(data))==T]
>
> Ouch! logical == TRUE is bad, logical == T is worse:
>
> data[, complete.cases(t(data))]
>
>
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: pd.mes at cbs.dk<mailto:pd.mes at cbs.dk>  Priv: PDalgd at
gmail.com<mailto:PDalgd at gmail.com>
>
>
>
>
>
>
>
>
>



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