On Tue, 14 Aug 2007, Wolfram Fischer wrote: > In help(unit) I read: > > The 'data' argument must be a list when the 'unit.length()' > is greater than 1. For example, 'unit(rep(1, 3), c("npc", > "strwidth", "inches"), data=list(NULL, "my string", NULL))'. > > In the newest R-versions it is not anymore allowed to let strings > in the data-argument for plain units, otherwise one gets the > following error: > Non-NULL value supplied for plain unit > > I have some labels. Between them I wanted to set a distance of 1.5 lines. > (I wanted to use that for a grid.layout for a legend: > The space is for the symbols.) > > labels <- c( 'xxxx:', 'a', 'bb', 'ccc', 'dddd', 'eeeee' ) > n <- length( labels ) > s <- as.list( c( labels[1], rep( labels[-1], each=2 ) ) ) > u <- unit( data=s, x=c( 1, rep( c( 1.5, 1 ), n-1 ) ), > units=c( 'strwidth', rep( c( 'lines', 'strwidth' ), n-1 ) ) ) > > How can I insert the NULL values into the list ``s''? > > To fill every second element of s with NULL, I tried: > s[ 2 * ( 1 : length( labels[-1] ) ) ] <- NULL > But this deletes every second element.
A value of list(NULL) is correct for inserting NULLs into lists. (More generally to substitute in a list you need a list value.) > The following would work: > s[ 2 * ( 1 : length( labels[-1] ) ) ] <- NA > But unit() does not accept NAs. More to the point, it does not accept logical vectors as NULL values. -- Brian D. Ripley, [EMAIL PROTECTED] 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@stat.math.ethz.ch 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.