apply vs. sapply

Hi,

sapply((1:NCOL(hermes)),function(x) hist(hermes[,x],main=names(hermes)[x]))

.......this works , but i would like use it with apply to generate many plots in one step!

sapply() already *has* generated many plots, if NCOL(hermes) > 1.
It's rather complicated to help if one does not know what kind of object
"hermes" is [I guess a data.frame, because names() seems to give
reasonable results for you]

####################################################################

apply((1:ncol(hermes)),2,function(x) hist(hermes[,x],main=names(hermes)[x]))

Error in apply(1:ncol(hermes), 2, function(x) hist(hermes[, x], main = names(hermes)[x])) :
        dim(X) must have a positive length

apply() expects an array or a matrix, but not a vector.
The function within apply works on rows / columns of the matrix given as
the first argument, so something like
 apply(hermes, 2, hist) 
should do the trick.

Anyway, for labeling purposes I'd highly recommend to use a loop rather
than apply().

Uwe Ligges

apply(hermes[,1:6],2,function(x) hist(hermes[,x],main=names(hermes)[x]))

Error in hist.default(hermes[, x], main = names(hermes)[x]) :
        `x' must be numeric

apply(hermes,2,function(x) hist(hermes[,x],main=names(hermes)[x]))

Error in hist.default(hermes[,x ], main = names(hermes)[x]) :
        `x' must be numeric

thanks for advance & regards

        [[alternate HTML version deleted]]

______________________________________________
R-help at stat.math.ethz.ch mailing list
http://www.stat.math.ethz.ch/mailman/listinfo/r-help

....hmm sorry "sometimes after several experiments" my graphic.device
(W2000/1.6.1)didn't popUp & only
a new start helps, but now it works :-)

# hermes is data.frame
apply(hermes,2,hist) #without names
sapply((1:ncol(hermes)),function(x) hist(hermes[,x],main=names(hermes)[x]))
#with col.names

thanks & regards,christian