[R] union of a list of logical values

[Liviu Andronic]

On Mon, Jul 22, 2013 at 11:37 AM, Prof Brian Ripley
<ripley at stats.ox.ac.uk> wrote:
> This really only makes sense for a list of logical vectors of the same
> length.  And by 'union' you seem to mean 'or'.
>
Indeed.


> Two approaches
>
> 1) Make a logical matrix and use apply(m, 1, any)
>
Of course! I tried apply(m, 1, "|") without luck, but I should have
used apply(m, 1, any) instead.

Thank you,
Liviu


> 2) Use Reduce(`|`, z)
>
>
>>
>> Consider the following:
>> x <- head(iris)
>> x[,c(2,4)] <- NA
>> x[c(2,4),] <- NA
>> # > x
>> # Sepal.Length Sepal.Width Petal.Length Petal.Width Species
>> # 1          5.1          NA          1.4          NA  setosa
>> # 2           NA          NA           NA          NA    <NA>
>> # 3          4.7          NA          1.3          NA  setosa
>> # 4           NA          NA           NA          NA    <NA>
>> # 5          5.0          NA          1.4          NA  setosa
>> # 6          5.4          NA          1.7          NA  setosa
>> z <- data.frame(!is.na(x))
>> # > z
>> # Sepal.Length Sepal.Width Petal.Length Petal.Width Species
>> # 1         TRUE       FALSE         TRUE       FALSE    TRUE
>> # 2        FALSE       FALSE        FALSE       FALSE   FALSE
>> # 3         TRUE       FALSE         TRUE       FALSE    TRUE
>> # 4        FALSE       FALSE        FALSE       FALSE   FALSE
>> # 5         TRUE       FALSE         TRUE       FALSE    TRUE
>> # 6         TRUE       FALSE         TRUE       FALSE    TRUE
>>
>> I did find a solution, but it seems more like a hack:
>>>
>>> ##union of logical values by rows (union of list of logical values)
>>> as.logical(rowSums(z))
>>
>> [1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE
>>>
>>> ##union of logical values by columns
>>> as.logical(colSums(z))
>>
>> [1]  TRUE FALSE  TRUE FALSE  TRUE
>>
>> Another unusable monstrosity is as follows:
>>>
>>> ##union of list of logical values
>>> z[[1]] | z[[2]] | z[[3]] | z[[4]] | z[[5]]
>>
>> [1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE
>>
>> Is there a more elegant way to approach this problem and obtain the
>> above logical vectors? Regards,
>> Liviu
>>
>>
>
>
> --
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595



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