Sampling from vectors 

set.seed(143)

sample(1:9)

[1] 8 6 4 1 7 2 9 5 3

sample(1:1000,size=20)

 [1] 658 171 191 428 806 768 307 120 506 340 190 962 437 274 477 935 363 469 933
[20]  79

sample(6,size=10,replace=TRUE)

 [1] 4 5 3 2 1 5 1 6 1 2