Sampling a random integer sequence

This function provides a very efficient way to pull an integer random sample sequence from an integer interval.

sample_seq(low, high, length)

Arguments

low

The lower limit of the interval (inclusive).

high

The higher limit of the interval (inclusive).

length

The length of the sample.

Value

An increasing numeric vector containing integers, the sample.

Details

The algorithm runs in O(length) expected time, even if high-low is big. It is much faster (but of course less general) than the builtin sample function of R.

References

Jeffrey Scott Vitter: An Efficient Algorithm for Sequential Random Sampling, ACM Transactions on Mathematical Software, 13/1, 58–67.

See also

Other other: convex_hull(), running_mean()

Author

Gabor Csardi csardi.gabor@gmail.com

Examples

rs <- sample_seq(1, 100000000, 10)
rs
#>  [1]  1854463  4841388 11085650 61479037 67193299 68060916 69854129 83816140
#>  [9] 87879279 97113747