Sorry for the stupid question, but is there the factorial function in
R? I tried to find it using help.search('factorial') but got nothing
appropriate.
Many thanks,
-Serge
Hi, ----- Original Message ----- From: "Serge Boiko" <boiko at demogr.mpg.de> To: <r-help at stat.math.ethz.ch> Sent: Friday, February 14, 2003 11:36 PM Subject: [R] factorial function> > Sorry for the stupid question, but is there the factorial function in > R? I tried to find it using help.search('factorial') but got nothing > appropriate.There isn't. But there are at least four different ways to do this -- from the S Programming Workshop (by Dr. Ross Ihaka): # Iteration fac1 <- function(n) { ans <- 1 for(i in seq(n)) ans <- ans * i ans } # Recursion fac2 <- function(n) if (n <= 0) 1 else n * fac(n - 1) # Vectorised fac3 <- function(n) prod(seq(n)) # Special Mathematical Function -- Gamma fac4 <- function(n) gamma(n+1) Of these Gamma is probably the most efficient. Note that the above hasn't got any debugging codes, you probably want to add them. Cheers, Kevin ------------------------------------------------ Ko-Kang Kevin Wang Master of Science (MSc) Student Department of Statistics University of Auckland New Zealand www.stat.auckland.ac.nz/~kwan022
Dear Serge, For factorial of x, you can use "gamma(x + 1)". Alternatively, you can install the gregmisc package which has a "factorial" function that does that (if I recall correctly). Best, On Friday 14 February 2003 11:36, Serge Boiko wrote:> Sorry for the stupid question, but is there the factorial function in > R? I tried to find it using help.search('factorial') but got nothing > appropriate. > Many thanks, > -Serge > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-help-- Ram?n D?az-Uriarte Bioinformatics Unit Centro Nacional de Investigaciones Oncol?gicas (CNIO) (Spanish National Cancer Center) Melchor Fern?ndez Almagro, 3 28029 Madrid (Spain) http://bioinfo.cnio.es/~rdiaz