[R] Using apply for logical conditions

[Bert Gunter]

Just for fun, here are another couple of versions that work for data frames.

For Reduce with "|"

do.call(pmax,c(mydata,na.rm=TRUE)) >0

and for "&"

do.call(pmin,c(mydata,na.rm=TRUE)) >0


 Cheers,

Bert Gunter
Genentech Nonclinical Biostatistics


On Mon, Aug 2, 2010 at 2:28 PM, Joshua Wiley <jwiley.psych at gmail.com> wrote:
> On Mon, Aug 2, 2010 at 2:08 PM, Michael Lachmann <lachmann at eva.mpg.de> wrote:
>>
>> Reduce() is much nicer, but I usually use
>>
>> rowSums(A) > 0 for 'or', and
>> rowSums(A) == ncols for 'and'.
>>
>> Which works slightly faster.
>
> For the sake of my own curiosity, I compared several of these options,
> but in case others are interested.....
>
>> boolean <- c(TRUE, FALSE, FALSE)
>>
>> set.seed(1)
>> mydata <- data.frame(X = sample(boolean, 10^7, replace = TRUE),
> +                      Y = sample(boolean, 10^7, replace = TRUE),
> +                      Z = sample(boolean, 10^7, replace = TRUE))
>>
>> system.time(opt1 <- apply(mydata, 1, any))
>   user  system elapsed
>  147.26    0.42  148.56
>> system.time(opt2 <- Reduce('|', mydata))
>   user  system elapsed
>   0.33    0.00    0.35
>> system.time(opt3 <- as.logical(rowSums(mydata, na.rm = TRUE)))
>   user  system elapsed
>   0.25    0.00    0.27
>> system.time(opt4 <- rowSums(mydata, na.rm = TRUE) > 0)
>   user  system elapsed
>   0.25    0.00    0.25
>>
>> identical(opt1, opt2)
> [1] TRUE
>> identical(opt1, opt3)
> [1] TRUE
>> identical(opt1, opt4)
> [1] TRUE
>>
>> rm(boolean, mydata, opt1, opt2, opt3, opt4)
>
>
>
>>
>> I noticed, though, that Reduce() doesn't work on matrices. Is there an
>> alternative for matrices, or do you have to convert the matrix first to a
>> data.frame, and then use Reduce?
>>
>>
>> --
>> View this message in context: http://r.789695.n4.nabble.com/Using-apply-for-logical-conditions-tp2310929p2310991.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> University of California, Los Angeles
> http://www.joshuawiley.com/
>
> ______________________________________________
> R-help at r-project.org 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.
>