Lottery

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg409] Lottery*From*: donald darling <ddarling at math.uci.edu>*Date*: Sun, 15 Jan 95 12:55:44 -0800

Yet another simple procedure to select, without replacement, a random sample S of size k from the first n integers. (S={};CS=Range[n];For[j=1,j<=k,j++, AppendTo[S,x={CS[[ Random[Integer,{1,n-j+1}] ]]}]; CS=Complement[CS,x] ];Flatten[S]) Note that if k>n/2 it is quicker to select a sample of size n-k and then choose CS, the complement of S, from the above.