findFn {sos}R Documentation

Search Help Pages

Description

Returns a data.frame from RSiteSearch(string, "function") which can be sorted and subsetted by user specifications and viewed in an HTML table.

Usage

findFn(string, maxPages = 20, sortby = NULL, verbose = 1, ...)
##???string(maxPages)

Arguments

string A character string. See RSiteSearch.
maxPages The maximum number of pages to download assuming 20 links per page.
sortby a character vector specifying how the data.frame returned should be sorted. Default = c('Count', 'MaxScore', 'TotalScore', 'Package', 'Score', 'Function') to sort descending on numerics and ascending on alphnumerics. Specifying sortby = c('c', 't', 'm') is equivalent to c('Count', 'TotalScore', 'MaxScore', 'Package', 'Score', 'Function').
verbose an integer: if 0, no output is printed to the console. The default 1 displays an initial line with the number of pages to be retrieved and the number of matches obtained; if the number of matches to be downloaded is less, this also is displayed on the initial line. This is followed by a second line counting the pages downloaded.
If greater than 1, additional information is provided on the download process.
... ignored

Details

findFn searchs the help pages of packages covered by the RSiteSearch archives. To restrict the search to only packages installed locally, use help.search.

1. Access the RSitSearch engine with string, restricting to "functions", storing Score, Package, Function, Date, Description, and Link in a data.frame.

2. Compute Count, MaxScore and TotalScore for each Package accessed. Combine them in a matrix PackageSummary.

3. Sort PackageSummary in the order defined by the occurrance of c('Count', 'MaxScore', 'TotalScore', 'Package') in sortby.

4. Merge PackageSummary with the data.frame of search matches.

5. Sort the combined data.frame as defined by sort..

6. Make the result have class c("findFn", "data.frame") and add attributes matches, PackageSummary, string, and call.

7. Done.

Value

an object of class c('findFn', 'data.frame') with columns and attributes as follows:

Columns
    Count
    Total number of matches downloaded in this package
    MaxScore
    maximum of the Score over all help pages selected within each Package. See Score below or the Namazu website (link below) for more information on how the score is determined.
    TotalScore
    sum of the Score over all help pages selected within each Package. See Score below or the Namazu website (link below) for more information on how the score is determined.
    Package
    Name of the package containing a help page meeting the search criteria
    Function
    Name of the help page found that meets the indicated search criterion.
    Date
    Date of the help page
    Score
    Score returned by RSiteSearch, discussed in the Namazu website (link below).
    Description
    Title of the help page
    Link
    Universal Resource Locator (URL) for the help page
Attributes
    matches
    an integer = total number of matches found by the search
    PackageSummary
    a data.frame with one row for each package and columns Package, Count, MaxScore, TotalScore, and Date, sorted as in the sort. argument.
    string
    the string argument in the call.
    call
    the matched call

Author(s)

Spencer Graves, Sundar Dorai-Raj, Romain Francois. Duncan Duncan Murdoch suggested the "???" alias for "findFn" and contributed the code for it.

Special thanks to Jonathan Baron and Andy Liaw. Baron maintains the RSiteSearch data base. Liaw and Baron created the RSiteSearch function in the utils package.

References

http://www.namazu.org/doc/tips.html.en#weight - reference on determining Score

See Also

help.search to search only installed packages. RSiteSearch, download.file http://finzi.psych.upenn.edu/search.html for a web interface to this same search capability with more general options. findFn searches only "Target: Functions" from that site, ignoring the R-help arcihves.

http://www.r-project.org/search.html for a list of alternative R search capabilities, each of which may be best for different types of inquiries.

findFunction for a completely different function with a similar name.

Examples

z <- findFn("spline", maxPages = 2)
# alternative
zq <- ???spline(2)


all.equal(z, zq)


# To search for 2 terms, not necessarily together:
RSS <- findFn('RSiteSearch function', 1)
matches(RSS)
# To search for an exact string, use braces:
RSS. <- findFn('{RSiteSearch function}', 1)
matches(RSS.) # list(nrow=0, matches=0)

[Package sos version 1.2-4 Index]