Good morning,
I'd like to look at the code for the R function head. When I type just the
word head, I get back
function(x, ...)
UseMethod("head")
<environment: namespace:utils>
I expected to see several lines of R code. Any suggestions?
Thanks,
Walt Paczkowski
On 16/07/2007 8:02 AM, Walter Paczkowski wrote:> Good morning, > > I'd like to look at the code for the R function head. When I type just the word head, I get back > > function(x, ...) > UseMethod("head") > <environment: namespace:utils> > > > I expected to see several lines of R code. Any suggestions?Even though it's not very informative, that really is the source for that function. For instructions on how to see the more useful stuff, see Uwe Ligges' article in the Oct 2006 R News (available at http://cran.r-project.org/doc/Rnews/Rnews_2006-4.pdf). Duncan Murdoch
Walter Paczkowski wrote:> Good morning, > > I'd like to look at the code for the R function head. When I type just the word head, I get back > > function(x, ...) > UseMethod("head") > <environment: namespace:utils> > > > I expected to see several lines of R code. Any suggestions?Have a look at: https://svn.r-project.org/R/trunk/src/library/utils/R/head.R Also, ?head shows methods for different types of objects, and you can see these with getAnywhere(head.default) or utils:::head.default> Thanks, > > Walt Paczkowski > > ______________________________________________ > R-help at stat.math.ethz.ch 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.-- Chuck Cleland, Ph.D. NDRI, Inc. 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894
Walter Paczkowski:> I'd like to look at the code for the R function head. ?When I type just > the word head, I get back > > function(x, ...) > UseMethod("head") > <environment: namespace:utils>This basically means that 'head' is a generic function that works in different ways for different classes of objects (data frames, matrices, tables &c.) Many function, e.g., 'plot' and 'mean', work the same way. Type ?UseMethod for a better/longer explanation. Now type methods(head) You will get: [1] head.data.frame* head.default* head.ftable* head.function* [5] head.matrix head.table* Now, ordinarily you should be able to write 'head.data.frame' to see the code for this function, but, since it is starred, '*', this doesn't work. The easiest way to get hold of it is using 'getAnywhere': getAnywhere(head.data.frame) -- Karl Ove Hufthammer