R: Metadata for a Data Frame

contents {Hmisc} | R Documentation

## Metadata for a Data Frame

### Description

`contents` is a generic method for which `contents.data.frame` is currently the only method. `contents.data.frame` creates an object containing the following attributes of the variables from a data frame: names, labels (if any), units (if any), number of factor levels (if any), factor levels, class, storage mode, and number of NAs. `print.contents.data.frame` will print the results, with options for sorting the variables. `html.contents.data.frame` creates HTML code for displaying the results. This code has hyperlinks so that if the user clicks on the number of levels the browser jumps to the correct part of a table of factor levels for all the `factor` variables. If long labels are present (`"longlabel"` attributes on variables), these are printed at the bottom and the `html` method links to them through the regular labels. Variables having the same `levels` in the same order have the levels factored out for brevity.

`contents.list` prints a directory of datasets when `sasxport.get` imported more than one SAS dataset.

### Usage

    contents(object, ...)
    ## S3 method for class 'data.frame'
    contents(object, sortlevels=FALSE, id=NULL,
      range=NULL, values=NULL, ...)
    ## S3 method for class 'contents.data.frame'
    print(x,
        sort=c('none','names','labels','NAs'), prlevels=TRUE, maxlevels=Inf,
        number=FALSE, ...)
    ## S3 method for class 'contents.data.frame'
    html(object,
               sort=c('none','names','labels','NAs'), prlevels=TRUE, maxlevels=Inf,
               levelType=c('list','table'),
               number=FALSE, nshow=TRUE, ...)
    ## S3 method for class 'list'
    contents(object, dslabels, ...)
    ## S3 method for class 'contents.list'
    print(x,
        sort=c('none','names','labels','NAs','vars'), ...)

### Arguments

`object` | a data frame. For `html` is an object created by `contents`. For `contents.list` is a list of data frames.
`sortlevels` | set to `TRUE` to sort levels of all factor variables into alphabetic order. This is especially useful when two variables use the same levels but in different orders. They will still be recognized by the `html` method as having identical levels if sorted.
`id` | an optional subject ID variable name that if present in `object` will cause the number of unique IDs to be printed in the contents header
`range` | an optional variable name that if present in `object` will cause its range to be printed in the contents header
`values` | an optional variable name that if present in `object` will cause its unique values to be printed in the contents header
`x` | an object created by `contents`
`sort` | Default is to print the variables in their original order in the data frame. Specify one of `"names"`, `"labels"`, or `"NAs"` to sort the variables by, respectively, alphabetically by names, alphabetically by labels, or by increaseing order of number of missing values. For `contents.list`, `sort` may also be the value `"vars"` to cause sorting by the number of variables in the dataset.
`prlevels` | set to `FALSE` to not print all levels of `factor` variables
`maxlevels` | maximum number of levels to print for a `factor` variable
`number` | set to `TRUE` to have the `print` and `latex` methods number the variables by their order in the data frame
`nshow` | set to `FALSE` to suppress outputting number of observations and number of `NA`s; useful when these counts would unblind information to blinded reviewers
`levelType` | By default, bullet lists of category levels are constructed in html. Set `levelType='table'` to put levels in html table format.
`...` | arguments passed from `html` to `format.df`, unused otherwise
`dslabels` | named vector of SAS dataset labels, created for example by `sasdsLabels`

### Value

an object of class `"contents.data.frame"` or `"contents.list"`. For the `html` method is an `html` character vector object.

### Author(s)

Frank Harrell
Vanderbilt University
f.harrell@vanderbilt.edu

### See Also

`describe`, `html`, `upData`

### Examples

    set.seed(1)
    dfr <- data.frame(x=rnorm(400),y=sample(c('male','female'),400,TRUE))
    contents(dfr)
    dfr <- upData(dfr, labels=c(x='Label for x', y='Label for y'))
    attr(dfr$x, 'longlabel') <-
     'A very long label for x that can continue onto multiple long lines of text'

    k <- contents(dfr)
    print(k, sort='names', prlevels=FALSE)
    ## Not run:
    html(k)
    html(contents(dfr))            # same result
    latex(k$contents)              # latex.default just the main information

    ## End(Not run)

[Package Hmisc version 4.0-3 Index]