On 22/07/2013 10:16, Liviu Andronic wrote:
Dear all,
How can I obtain the union of a list of logical values?
This really only makes sense for a list of logical vectors of the same
length. And by 'union' you seem to mean 'or'.
Two approaches
1) Make a logical matrix and use apply(m, 1, any)
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, rip...@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
______________________________________________
R-help@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.
