R devel - Sep 2005 - error in apply help file? (PR#8118)

Gents: (alas, I think no ladies need to be included in the salutation)

The apply()  Help file says
"...
If the calls to FUN return vectors of different lengths, apply returns a
list of length dim(X)[MARGIN]. "

Shouldn't that be:

"If the calls to FUN return vectors of different lengths, apply returns a
list of length prod(dim(X)[MARGIN]). "

Also, might you wish to add:

"This list has a dim attribute of MARGIN. That is, if VALUE is the returned
list, dim(VALUE) = MARGIN and the values in VALUE can be accessed by the
usual array subscripting operations."

Further, it might also be useful to add the following to your Examples code:

## Example with different lengths for each call
z <- array(1:24,dim=2:4)
zseq <- apply(z,1:2,function(x)seq(length=max(x)))
zseq  ## displayed as a 2 x 3 matrix
typeof(zseq) ## list
dim(zseq) ## 2 3
zseq[1,]


Feel free to ignore these suggestions, of course. 

Cheers,

-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA

gunter.berton at gene.com wrote:
> Gents: (alas, I think no ladies need to be included in the salutation)

May I ask why you think R-devel (to which R-bugs stuff is forwarded) is 
only read by males?

Sounds a little bit discriminating ("Only males produce bugs, females 
simply produce perfect code and do not need to read R-devel mails."??!). 
Hence, I'd like to complain in this case.

Uwe Ligges


> The apply()  Help file says
> "...
> If the calls to FUN return vectors of different lengths, apply returns a
> list of length dim(X)[MARGIN]. "
> 
> Shouldn't that be:
> 
> "If the calls to FUN return vectors of different lengths, apply
returns a
> list of length prod(dim(X)[MARGIN]). "
> 
> Also, might you wish to add:
> 
> "This list has a dim attribute of MARGIN. That is, if VALUE is the
returned
> list, dim(VALUE) = MARGIN and the values in VALUE can be accessed by the
> usual array subscripting operations."
> 
> Further, it might also be useful to add the following to your Examples
code:
> 
> ## Example with different lengths for each call
> z <- array(1:24,dim=2:4)
> zseq <- apply(z,1:2,function(x)seq(length=max(x)))
> zseq  ## displayed as a 2 x 3 matrix
> typeof(zseq) ## list
> dim(zseq) ## 2 3
> zseq[1,]
> 
> 
> Feel free to ignore these suggestions, of course. 
> 
> Cheers,
> 
> -- Bert Gunter
> Genentech Non-Clinical Statistics
> South San Francisco, CA
> 
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