Try this:

data(list = DS$results[,'Item'], package = 'vcdExtra', envir = ne <-
new.env())
cbind(do.call(rbind, eapply(ne, function(x)data.frame(class = class(x), dim
= paste(dim(x), collapse = 'x')))), Title = DS$results[,'Title'])

On Mon, Oct 25, 2010 at 1:45 PM, Michael Friendly <friendly@yorku.ca> wrote:

> I can use data() to find the available datasets in a package, but I'd like
> to extract and display some additional
> information for each dataset  than what is provided by data(), e.g.,
> class() and dim() for datasets for which
> these are available.  I'm stuck on using using lapply properly with
> objects, rather than the names of objects
> that I get from data()
>
> Example:
>
> > DS <- data(package="vcdExtra")
> > DS$results[,c("Item", "Title")]
>      Item          Title
>  [1,] "Abortion"    "Abortion Opinion Data"
>  [2,] "Bartlett"    "Bartlett data on plum root cuttings"
>  [3,] "Caesar"      "Risk Factors for Infection in Caesarian Births"
>  [4,] "Cancer"      "Survival of Breast Cancer Patients"
>  [5,] "Detergent"   "Detergent preference data"
>  [6,] "Dyke"        "Sources of knowledge of cancer"
>  [7,] "GSS"         "General Social Survey-- Sex and Party affiliation"
>  [8,] "Gilby"       "Clothing and Intelligence Rating of Children"
>  [9,] "Heart"       "Sex, Occupation and Heart Disease"
> [10,] "Heckman"     "Labour Force Participation of Married Women 1967-1971"
> [11,] "Hoyt"        "Minnesota High School Graduates"
> [12,] "ICU"         "Death in the ICU"
> [13,] "JobSat"      "Cross-classification of job satisfaction by income"
> [14,] "Mental"      "Mental impariment and parents SES"
> [15,] "Mobility"    "Social Mobility data"
> [16,] "TV"          "TV Viewing Data"
> [17,] "Vietnam"     "Student Opinion About the War in Vietnam"
> [18,] "Yamaguchi87" "Occupational Mobility in Three Countries"
> > unlist(lapply(as.list(DS$results[,c("Item") ]), FUN=class))
>  [1] "character" "character" "character" "character" "character"
> "character" "character"
>  [8] "character" "character" "character" "character" "character"
> "character" "character"
> [15] "character" "character" "character" "character"
>
> Wanted: something like the results of doing
>
> > class(Abortion)
> [1] "table"
> > dim(Abortion)
> [1] 2 2 2
> > class(Mental)
> [1] "data.frame"
> > dim(Mental)
> [1] 24  3
> >
> for all datasets in Item, giving a display like
>
> Item      class       dim     Title
> Abortion  table       2x2x2   Abortion Opinion Data
> Mental    data.frame  24x2    Mental impariment and parents SES
>
> --
> Michael Friendly     Email: friendly AT yorku DOT ca
> Professor, Psychology Dept.
> York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
> 4700 Keele Street    Web:   http://www.datavis.ca
> Toronto, ONT  M3J 1P3 CANADA
>
> ______________________________________________
> 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.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

