Return the first or last part of a BibEntry object

Prints the first or last entries of a BibEntry object (via message) and returns them invisibly (via invisible).

Usage

# S3 method for class 'BibEntry'
head(x, n = 6L, suppress.messages = TRUE, ...)

# S3 method for class 'BibEntry'
tail(x, n = 6L, suppress.messages = TRUE, ...)

Arguments

x

an object of class BibEntry.

n

a single integer. If positive, size for the resulting object: number of elements for a vector (including lists), rows for a matrix or data frame or lines for a function. If negative, all but the n last/first number of elements of x.

suppress.messages

boolean; should the head/tail entries be printed via message?

...

arguments to be passed to or from other methods.

Value

an object of class BibEntry.

Details

If suppress.messages is FALSE, the head/tail entries are output to the console along with some additional formatting for the ‘bibtype’ and ‘key’, in addition to invisibly returning the entries.

Examples

if (requireNamespace("bibtex")) {
    file <- system.file("Bib", "biblatexExamples.bib", package = "RefManageR")
    BibOptions(check.entries = FALSE)
    bib <- ReadBib(file)
    tail(bib, 2, suppress.messages = FALSE)
    bib <- head(bib, 1, suppress.messages = TRUE)
}
#> [[91]] Thesis: geer
#> [1] I. de Geer. “Earl, Saint, Bishop, Skald~- and Music. The Orkney
#> Earldom of the Twelfth Century. A Musicological Study”. PhD thesis.
#> Uppsala: Uppsala Universitet, 1985.
#> 
#> [[92]] Thesis: loh
#> [1] N. C. Loh. “High-Resolution Micromachined Interferometric
#> Accelerometer”. MA Thesis. Cambridge, Mass.: Massachusetts Institute of
#> Technology, 1992.