[R] matrix manipulation question

Henric Winell
Fri, 27 Mar 2015 12:29:40 -0000

On 2015-03-27 11:41, St?phane Adamowicz wrote:

> 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]

Peter's point, I guess, is that

1. complete.cases(t(Y)) is already a vector of logicals
2. T (and F) can be redefined, so what if T <- FALSE?


Henric Winell



>
> 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> a ?crit
:
>
>>
>> On 27 Mar 2015, at 09:58 , St?phane Adamowicz <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  Priv: PDalgd at gmail.com
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
> _________________________________
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