diff options
| -rw-r--r-- | goat.R | 31 |
1 files changed, 31 insertions, 0 deletions
@@ -3,6 +3,17 @@ # http://en.wikipedia.org/wiki/Monty_hall_problem # SJP 25 Oct 2007 # + +#------------------------ Instructions ----------------- +# Read the wikipedia article for background +# source this file into R. +# The game() function is played out, using both strategies, swapping or not swapping +# After Monty opens one of the doors that you didn't choose and invites you to swap. + +# Play around with the game() function, +# changing the number of trials (iterations) and doors etc. +# The comments in the code are fairly good (EIIDSSM!) +# # consts NUMDOORS <- 3 # GOAT <- 0 @@ -24,6 +35,26 @@ allocPrize <- function(d=NUMDOORS){ door[getDoor()] <- PRIZE # put the prize behind a door return(door) } +####################################################################### +# Get a result based on a probability (default is 0.5) +# a typical usage is: 'if(pr(x)) then ... +pr <- function(x = 0.5){ + if (!length(x)) {return()} + if (x<0 || x>1) stop(" prob out of range\n") + return(ifelse(rbinom(length(x), 1, x), TRUE, FALSE)) +} +####################################################################### +# junkYard() place a silent stop() at the end of a source file +# in effect, the rest of the file is the junkYard of half-good script +junkYard <- function(){ + op <- getOption('show.error.messages') # save settings +# options(show.error.messages = F) # don't warn + cat('called from junkYard()\n') +# print( parent.frame()) + try(stop(), silent=T) + return('how did this get here?') +} + ############################################################### # game() function |