You can calculate how many ways can k items be taken from n items by using the following command.
choose(n=5,k=2);
Load the file example.csv See Loading Data for help.
example.data <- read.csv(file="http://homepages.gac.edu/~anienow2/MCS_142/R/example.csv", header=TRUE, sep=",")
Generate all possible combinations of size 2 from a list.
my.list <- example.data$Name # creates a list of names
combn(my.list, 2); # Produces all possible combinations of size = 2 from my.list.
## [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
## [1,] Shelly Shelly Shelly Shelly Alvin Alvin Alvin Simon Simon Theo
## [2,] Alvin Simon Theo Nicki Simon Theo Nicki Theo Nicki Nicki
## Levels: Alvin Nicki Shelly Simon Theo
Each column is one combination. NOTE, this is not a randomly generated list. The sample()
function should be used for generating random samples.
To calculate the number of possible permutations for a list of n distinct items use the following command. In this case, n = 5.
factorial(x=5);
## [1] 120
Mathematicss, Computer Science, and Statistics Department Gustavus Adolphus College